To see the other types of publications on this topic, follow the link: Chi square tests.
Dissertations / Theses on the topic 'Chi square tests'
Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles
Consult the top 50 dissertations / theses for your research on the topic 'Chi square tests.'
Next to every source in the list of references, there is an 'Add to bibliography' button. Press on it, and we will generate automatically the bibliographic reference to the chosen work in the citation style you need: APA, MLA, Harvard, Chicago, Vancouver, etc.
You can also download the full text of the academic publication as pdf and read online its abstract whenever available in the metadata.
Browse dissertations / theses on a wide variety of disciplines and organise your bibliography correctly.
1
Roberts, Georgia Ruth Carleton University Dissertation Psychology. "Contributions to chi-squared tests with survey data." Ottawa, 1985.
Find full text
2
De, Champlain André F. "Assessing test dimensionality using two approximate chi-square statistics." Thesis, University of Ottawa (Canada), 1992. http://hdl.handle.net/10393/7848.
Full text
3
Mullen, Jerry D. (Jerry Davis). "A Comparison of Some Continuity Corrections for the Chi-Squared Test in 3 x 3, 3 x 4, and 3 x 5 Tables." Thesis, North Texas State University, 1987. https://digital.library.unt.edu/ark:/67531/metadc331001/.
Full textAbstract:
This study was designed to determine whether chis-quared based tests for independence give reliable estimates (as compared to the exact values provided by Fisher's exact probabilities test) of the probability of a relationship between the variables in 3 X 3, 3 X 4 , and 3 X 5 contingency tables when the sample size is 10, 20, or 30. In addition to the classical (uncorrected) chi-squared test, four methods for continuity correction were compared to Fisher's exact probabilities test. The four methods were Yates' correction, two corrections attributed to Cochran, and Mantel's correction. The study was modeled after a similar comparison conducted on 2 X 2 contingency tables and published by Michael Haber.
4
Pang, Xiao L. "Assessing the performance of the approximate chi-square and Stout's T statistics with different test structures." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1999. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape8/PQDD_0010/NQ52277.pdf.
Full text
5
Brace, Jordan. "Type I error rates and power of robust chi-square difference tests in investigations of measurement invariance." Thesis, University of British Columbia, 2015. http://hdl.handle.net/2429/54538.
Full textAbstract:
A Monte Carlo simulation study was conducted to investigate Type I error rates and power of several corrections for non-normality to the normal theory chi-square difference test in the context of evaluating measurement invariance via Structural Equation Modeling (SEM). Studied statistics include: 1) the uncorrected difference test, DML, 2) Satorra’s (2000) original computationally intensive correction, DS0, 3) Satorra and Bentler’s (2001) simplified correction, DSB1, 4) Satorra and Bentler’s (2010) strictly positive correction, DSB10, and 5) a hybrid procedure, DSBH (Asparouhov & Muthén, 2010), which is equal to DSB1 when DSB1 is positive, and DSB10 when DSB1 is negative. Multiple-group data were generated from confirmatory factor analytic models invariant on some but not all parameters. A series of six nested invariance models was fit to each generated dataset. Population parameter values had little influence on the relative performance of the scaled statistics, while level of invariance being tested did. DS0 was found to over-reject in many Type I error conditions, and it is suspected that high observed rejection rates in power conditions are due to a general positive bias. DSB1 generally performed well in Type I error conditions, but severely under-rejected in power conditions. DSB10 performed reasonably well and consistently in both Type I error and power conditions. We recommend that researchers use the strictly positive corrected difference test, DSB10, to evaluate measurement invariance when data are not normally distributed.<br>Arts, Faculty of<br>Psychology, Department of<br>Graduate
6
Chuang, Jenny. "Investigation of Type I error rates of three versions of robust chi-square difference tests in structural equation modeling." Thesis, University of British Columbia, 2013. http://hdl.handle.net/2429/44856.
Full textAbstract:
A Monte Carlo simulation was conducted to investigate the Type I error rates of several versions of chi-square difference tests for nonnormal data in confirmatory factor analysis (CFA) models. The studied statistics include: 1) the original uncorrected difference test, D, obtained by taking the difference of the ML chi-squares for the respective models; 2) the original robust difference test, DR₁, due to Satorra and Bentler (2001); 3) the recent modification to this test, DR₂, which ensures that the statistic remains positive (Satorra & Bentler, 2010); and 4) a hybrid statistic, DH, proposed by Asparouhov and Muthén (2010), which is equal to DR₁ when DR₁ > 0, and otherwise is equal to DR₁. Types of constraints studied included constraining factor correlations to 0, constraining factor correlations to 1, and constraining factor loadings to equal each other within or across factors. An interesting finding was that the uncorrected test appeared to be robust to nonnormality when the constraint was setting factor correlations to zero. The robust tests performed well and similarly to each other in many conditions. The new strictly positive test, DR₂ exhibited slightly inflated rejection rates in conditions that involved constraining factor loadings, while DR₁ and DH exhibited rejection rates slightly below nominal in conditions that involved constraining factor correlations or factor loadings. While more research is needed on the new strictly positive test, the original robust difference test or the hybrid procedure are tentatively recommended.
7
Steele, Michael C., and n/a. "The Power of Categorical Goodness-Of-Fit Statistics." Griffith University. Australian School of Environmental Studies, 2003. http://www4.gu.edu.au:8080/adt-root/public/adt-QGU20031006.143823.
Full textAbstract:
The relative power of goodness-of-fit test statistics has long been debated in the literature. Chi-Square type test statistics to determine 'fit' for categorical data are still dominant in the goodness-of-fit arena. Empirical Distribution Function type goodness-of-fit test statistics are known to be relatively more powerful than Chi-Square type test statistics for restricted types of null and alternative distributions. In many practical applications researchers who use a standard Chi-Square type goodness-of-fit test statistic ignore the rank of ordinal classes. This thesis reviews literature in the goodness-of-fit field, with major emphasis on categorical goodness-of-fit tests. The continued use of an asymptotic distribution to approximate the exact distribution of categorical goodness-of-fit test statistics is discouraged. It is unlikely that an asymptotic distribution will produce a more accurate estimation of the exact distribution of a goodness-of-fit test statistic than a Monte Carlo approximation with a large number of simulations. Due to their relatively higher powers for restricted types of null and alternative distributions, several authors recommend the use of Empirical Distribution Function test statistics over nominal goodness-of-fit test statistics such as Pearson's Chi-Square. In-depth power studies confirm the views of other authors that categorical Empirical Distribution Function type test statistics do not have higher power for some common null and alternative distributions. Because of this, it is not sensible to make a conclusive recommendation to always use an Empirical Distribution Function type test statistic instead of a nominal goodness-of-fit test statistic. Traditionally the recommendation to determine 'fit' for multivariate categorical data is to treat categories as nominal, an approach which precludes any gain in power which may accrue from a ranking, should one or more variables be ordinal. The presence of multiple criteria through multivariate data may result in partially ordered categories, some of which have equal ranking. This thesis proposes a modification to the currently available Kolmogorov-Smirnov test statistics for ordinal and nominal categorical data to account for situations of partially ordered categories. The new test statistic, called the Combined Kolmogorov-Smirnov, is relatively more powerful than Pearson's Chi-Square and the nominal Kolmogorov-Smirnov test statistic for some null and alternative distributions. A recommendation is made to use the new test statistic with higher power in situations where some benefit can be achieved by incorporating an Empirical Distribution Function approach, but the data lack a complete natural ordering of categories. The new and established categorical goodness-of-fit test statistics are demonstrated in the analysis of categorical data with brief applications as diverse as familiarity of defence programs, the number of recruits produced by the Merlin bird, a demographic problem, and DNA profiling of genotypes. The results from these applications confirm the recommendations associated with specific goodness-of-fit test statistics throughout this thesis.
8
Steele, Michael C. "The Power of Categorical Goodness-Of-Fit Statistics." Thesis, Griffith University, 2003. http://hdl.handle.net/10072/366717.
Full textAbstract:
The relative power of goodness-of-fit test statistics has long been debated in the literature. Chi-Square type test statistics to determine 'fit' for categorical data are still dominant in the goodness-of-fit arena. Empirical Distribution Function type goodness-of-fit test statistics are known to be relatively more powerful than Chi-Square type test statistics for restricted types of null and alternative distributions. In many practical applications researchers who use a standard Chi-Square type goodness-of-fit test statistic ignore the rank of ordinal classes. This thesis reviews literature in the goodness-of-fit field, with major emphasis on categorical goodness-of-fit tests. The continued use of an asymptotic distribution to approximate the exact distribution of categorical goodness-of-fit test statistics is discouraged. It is unlikely that an asymptotic distribution will produce a more accurate estimation of the exact distribution of a goodness-of-fit test statistic than a Monte Carlo approximation with a large number of simulations. Due to their relatively higher powers for restricted types of null and alternative distributions, several authors recommend the use of Empirical Distribution Function test statistics over nominal goodness-of-fit test statistics such as Pearson's Chi-Square. In-depth power studies confirm the views of other authors that categorical Empirical Distribution Function type test statistics do not have higher power for some common null and alternative distributions. Because of this, it is not sensible to make a conclusive recommendation to always use an Empirical Distribution Function type test statistic instead of a nominal goodness-of-fit test statistic. Traditionally the recommendation to determine 'fit' for multivariate categorical data is to treat categories as nominal, an approach which precludes any gain in power which may accrue from a ranking, should one or more variables be ordinal. The presence of multiple criteria through multivariate data may result in partially ordered categories, some of which have equal ranking. This thesis proposes a modification to the currently available Kolmogorov-Smirnov test statistics for ordinal and nominal categorical data to account for situations of partially ordered categories. The new test statistic, called the Combined Kolmogorov-Smirnov, is relatively more powerful than Pearson's Chi-Square and the nominal Kolmogorov-Smirnov test statistic for some null and alternative distributions. A recommendation is made to use the new test statistic with higher power in situations where some benefit can be achieved by incorporating an Empirical Distribution Function approach, but the data lack a complete natural ordering of categories. The new and established categorical goodness-of-fit test statistics are demonstrated in the analysis of categorical data with brief applications as diverse as familiarity of defence programs, the number of recruits produced by the Merlin bird, a demographic problem, and DNA profiling of genotypes. The results from these applications confirm the recommendations associated with specific goodness-of-fit test statistics throughout this thesis.<br>Thesis (PhD Doctorate)<br>Doctor of Philosophy (PhD)<br>Australian School of Environmental Studies<br>Full Text
9
Boulet, John R. "A Monte Carlo comparison of the Type I error rates of the likelihood ratio chi-square test statistic and Hotelling's two-sample T2 on testing the differences between group means." Thesis, University of Ottawa (Canada), 1990. http://hdl.handle.net/10393/5708.
Full textAbstract:
The present paper demonstrates how Structural Equation Modelling (SEM) can be used to formulate a test of the difference in means between groups on a number of dependent variables. A Monte Carlo study compared the Type I error rates of the Likelihood Ratio (LR) Chi-square ($\chi\sp2$) statistic (SEM test criterion) and Hotelling's two-sample T$\sp2$ statistic (MANOVA test criterion) in detecting differences in means between two independent samples. Seventy-two conditions pertaining to average sample size ((n$\sb1$ + n$\sb2$)/2), extent of inequality of sample sizes (n$\sb1$:n$\sb2$), number of variables (p), and degree of inequality of variance-covariance matrices ($\Sigma\sb1$:$\Sigma\sb2$) were modelled. Empirical sampling distributions of the LR $\chi\sp2$ statistic and Hotelling's T$\sp2$ statistic consisted fo 2000 samples drawn from multivariate normal parent populations. The actual proportion of values that exceeded the nominal levels are presented. The results indicated that, in terms of maintaining Type I error rates that were close to the nominal levels, the LR $\chi\sp2$ statistic and Hotelling's T$\sp2$ statistic were comparable when $\Sigma\sb1$ = $\Sigma\sb2$ and (n$\sb1$ + n$\sb2$)/2:p was relatively large (i.e., 30:1). However, when $\Sigma\sb1$ = $\Sigma\sb2$ and (n$\sb1$ + n$\sb2$)/2:p was small (i.e., 10:1) Hotelling's T$\sp2$ statistic was preferred. When $\Sigma\sb{1} \not=\Sigma\sb2$ the LR $\chi\sp2$ statistic provided more appropriate Type I error rates under all of the simulated conditions. The results are related to earlier findings, and implications for the appropriate use of the SEM method of testing for group mean differences are noted.
10
Wolniczak, Isabella, José A. Cáceres-DelAguila, Jorge L. Maguiña, and Antonio Bernabe-Ortiz. "Fruits and vegetables consumption and depressive symptoms: A population-based study in Peru." Public Library of Science, 2017. http://hdl.handle.net/10757/622277.
Full textAbstract:
Objectives: Among different factors, diet patterns seem to be related to depression. The aim of this study was to evaluate the association between the consumption of fruits and/or vegetables and depressive symptoms. Methodology/Principal findings: A secondary data analysis was conducted using information from a population-based survey from 25 regions from Peru. The outcome was the presence of depressive symptoms according to the Patient Health Questionnaire (cutoff 15 to define major depressive syndrome); whereas the exposure was the self-reported consumption of fruits and/or vegetables (in tertiles and using WHO recommendation 5 servings/day). The association of interest was evaluated using Poisson regression models controlling for the complex-sample survey design and potential confounders. Data from 25,901 participants were analyzed, mean age 44.2 (SD: 17.7) and 13,944 (54.0%) women. Only 910 (3.8%; 95%CI: 3.5%–4.2%) individuals reported consuming 5 servings of fruits and/or vegetables/day; whereas 819 (2.8%; 95%CI: 2.5%–3.1%) had depressive symptoms. Those in the lowest tertile of fruits and/or vegetables consumption had greater prevalence of depressive symptoms (PR = 1.88; 95% CI: 1.39–2.55) than those in the highest tertile. This association was stronger with fruits (PR = 1.92; 95%CI: 1.46–2.53) than vegetables (PR = 1.42; 95%CI: 1.05–1.93) alone. Conclusions: An inverse relationship between consumption of fruits and/or vegetables and depressive symptoms is reported. Less than 5% of subjects reported consuming the amount of fruits and vegetables recommended by the WHO. There is a need to implement strategies to promote better diet patterns with potential impact on mental health. © 2017 Wolniczak et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
11
Mbabu, Loyd G. "A CONTENT ANALYSIS OF INFORMATION LITERACY COURSES IN MASTER’S DEGREE PROGRAMS OF LIBRARY AND INFORMATION STUDIES." Ohio University / OhioLINK, 2007. http://rave.ohiolink.edu/etdc/view?acc_num=ohiou1178045906.
Full text
12
Munasinghe, Wijith Prasantha. "Cluster-based lack of fit tests for nonlinear regression models." Diss., Manhattan, Kan. : Kansas State University, 2010. http://hdl.handle.net/2097/2366.
Full text
13
Matějíček, Jaroslav. "Generátory náhodných čísel pro kryptografii." Master's thesis, Vysoké učení technické v Brně. Fakulta informačních technologií, 2012. http://www.nusl.cz/ntk/nusl-236519.
Full textAbstract:
The content of this thesis is the design and statistical tests of two di erent hardware random number generators. It also includes an overview of the sources of entropy, algorithms used to correct deviations from the normal distribution and the description of statistical tests.
14
Barret, Beverley, and n/a. "Users and an online catalogue : an evaluation of the OPAC at the Dixson Library, University of New England." University of Canberra. Information, Language & Culture Studies, 1989. http://erl.canberra.edu.au./public/adt-AUC20060607.162838.
Full textAbstract:
This thesis reports on a study undertaken at the Dixson Library, University of New
England. The purpose of the study was to develop an understanding of users of online
public access catalogues (OPACs). The understanding gained from the study will assist
in the development of improvements to the Library's OPAC, and increase user ability to
access information from the OPAC. The study replicated the user questionnaire of the
Online Patron Access Project, sponsored by the Council on Library Resources (CLR) in
1981/83. The questionnaire was modified slightly to suit conditions at the Dixson
Library.
The study addressed nine research questions relating to the users, their reactions,
attitudes, experiences and problems. The user task and their suggestions for
improvement were also addressed. The study formally tested three propositions between
the variables user task, success and attitudes in relation to OPAC users.
The findings show the analysis of the responses for the population as a whole, and,
where relevant, for eight groups of student respondents based on their academic
affiliation. The student population was of particular importance because of the
preponderance of external students at the University of New England. The differences in
the findings between the groups of students were discussed, and where possible,
explained. The three formal propositions were tested by carrying out Chi square tests for
the values of each variable. Nine significant relationships were found.
Comparisons were made between the Dixson Library findings and those of the CLR
study. Recommendations and conclusions were drawn from the study, including areas
for further research.
15
Netto, Jôira Conceição dos Santos. "Análise de dados categóricos e aplicações /." Rio Claro, 2019. http://hdl.handle.net/11449/184153.
Full textAbstract:
Orientador: Selene Maria Coelho Loibel<br>Resumo: Esta dissertação tem como foco a análise de dados categóricos, uma parte integrante da Análise Multivariada que interpreta a informação que está contida em dados discretos provenientes de contagens de eventos, possuindo características de nidas pela combinação das categorias de duas ou mais variáveis. A análise de dados categóricos é de grande importância dentro da Estatística pois tem aplicabilidade em variadas áreas do conhecimento. Os dados utilizados, foram coletados através de um question ário aplicado aos alunos de cinco Escolas Técnicas Estaduais (Etec) que nalizaram os cursos técnicos em 2018 e 2019. A pesquisa teve como objetivo obter dados locais e analisar se os alunos pretendem trabalhar ou continuar estudando na mesma área do curso que estão concluindo, se os alunos estão satisfeitos com os cursos que estão fazendo, se pretendem voltar para Etec e fazer outro curso complementar, entre outros questionamentos. Devido à natureza dos dados obtidos, as técnicas de análise de dados categóricos são adequadas e devem ser aplicadas para modelar e fazer inferências sobre os aspectos de interesse. Esta análise pode levar a resultados que serão de grande utilidade para essas Etecs.<br>Abstract: This dissertation focuses on the Categorical Data Analysis, an integral part of the Multivariate Analysis, which interprets embedded information in discrete data resulting from event counts, having characteristics de ned by combinations of categories from two or more variables. The categorical data analysis is of considerable importance within Statistics since it has a wide applicability in several areas of knowledge. The data set used was collected through a questionnaire applied to students from ve Public Technical Schools (Etec) that nished the technical courses in 2018 and 2019. The research aims to gather local data and analyze whether students intend to work or continue studying in the same eld of the technical course they are completing, whether students are satis ed with the courses they are attending, whether they want to go back to Etec and take another complementary course, among other questions. Due to the nature of the data obtained, categorized data analysis techniques are adequate and should be applied to model and make inferences about the aspects of interest. This analysis can be leaded to outcomes that will be very useful to these Etecs.<br>Mestre
16
Price, Emily A. "Item Discrimination, Model-Data Fit, and Type I Error Rates in DIF Detection using Lord's χ2, the Likelihood Ratio Test, and the Mantel-Haenszel Procedure". Ohio University / OhioLINK, 2014. http://rave.ohiolink.edu/etdc/view?acc_num=ohiou1395842816.
Full text
17
Cheng, Kai-ho. "The Chi-square test when the expected frequencies are less than 5." Click to view the E-thesis via HKUTO, 2007. http://sunzi.lib.hku.hk/HKUTO/record/B39558708.
Full text
18
鄭啟豪 and Kai-ho Cheng. "The Chi-square test when the expected frequencies are less than 5." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2007. http://hub.hku.hk/bib/B39558708.
Full text
19
Carroll, Gretchen Kay. "AN EXAMINATION OF THE RELATIONSHIP BETWEEN PERSONALITY TYPE, SELF PERCEPTION ACCURACY AND TRANSFORMATIONAL LEADERSHIP PRACTICES OF FEMALE HOSPITAL LEADERS." Bowling Green State University / OhioLINK, 2010. http://rave.ohiolink.edu/etdc/view?acc_num=bgsu1288189512.
Full text
20
Purutcuoglu, Vilda. "Unit Root Problems In Time Series Analysis." Master's thesis, METU, 2004. http://etd.lib.metu.edu.tr/upload/2/12604701/index.pdf.
Full textAbstract:
In time series models, autoregressive processes are one of the most popular stochastic processes, which are stationary under certain conditions. In this study we consider nonstationary autoregressive models of order one, which have iid random errors. One of the important nonstationary time series models is the unit root process in AR (1), which simply implies that a shock to the system has permanent effect through time. Therefore, testing unit root is a very important problem.
However, under nonstationarity, any estimator of the autoregressive coefficient does not have a known exact distribution and the usual t &ndash<br>statistic is not accurate even if the sample size is very large. Hence,Wiener process is invoked to obtain the asymptotic distribution of the LSE under normality. The first four moments of under normality have been worked out for large n.
In 1998, Tiku and Wong proposed the new test statistics and whose type I error and power values are calculated by using three &ndash<br>moment chi &ndash<br>square or four &ndash<br>moment F approximations. The test statistics are based on the modified maximum likelihood estimators and the least square estimators, respectively. They evaluated the type I errors and the power of these tests for a family of symmetric distributions (scaled Student&rsquo<br>s t). In this thesis, we have extended this work to skewed distributions, namely, gamma and generalized logistic.
21
Stasiukaitytė, Irma. "Infarkto gydymo įvairiais vaistais statistiniai tyrimo metodai." Master's thesis, Lithuanian Academic Libraries Network (LABT), 2004. http://vddb.library.lt/obj/LT-eLABa-0001:E.02~2004~D_20040610_174400-77084.
Full textAbstract:
The goal of the present thesis is to ascertain the impact of different drugs, intended for the infarction treatment; investigation of the other factors, which may stipulate bleeding in the course of the operation and within the post-operation period. The investigation was carried out in two stages. During the first stage the data was accumulated for processing (investigation of the sample homogeneity and normality); the second stage implied solution of the statistical tasks (solution of the tasks, which correspond to the goals of the thesis). The methods of data analysis and the models of binary logistic and linear logistic regression were applied. 89 patients, who survived the myocarditis infarction, were investigated and it was ascertained that there is no huge difference in between the tranexamic acid and aprotinin. The bleeding complications may be caused by aspirin, which has been used before the operation. One of the complications, i.e. the drainage, may be predicted, judging from the amount of haemoglobin, haematocrit in the blood as well as creatinin. The model of the binary logistic regression assisted us in drawing the conclusion that smoking, hypothermia, euroscore and other factors produce an impact upon the bleeding complications.
22
Caprio, Joseph M., Harold C. Fritts, Richard L. Holmes, David M. Meko, and Deborah L. Hemming. "A Chi-Square Test for the Association and Timing of Tree Ring-Daily Weather Relationships: A New Technique for Dendroclimatology." Tree-Ring Society, 2003. http://hdl.handle.net/10150/262549.
Full textAbstract:
This study introduces a new analytical procedure based on the chi-square (x²) statistic to evaluate tree- ring weather relationships. An iterative x² method, developed previously for relating annual crop production to daily values of meteorological measurements, is applied to tree-ring data and compared to results obtained from correlation and bootstrapped response function analyses. All three analytical procedures use a southern Arizona chronology (Pinus arizonica Engelm.) and the latter two use monthly average meteorological data. The x² analysis revealed most of the relationships exhibited by the correlation and response function analyses as well as new linear and nonlinear associations. In addition, cardinal values were obtained that define daily thresholds of the meteorological variables at which the limitation to growth becomes significant. Some of the associations are plausible from the physical system but require more study to confirm or refute a real cause and effect. A few associations appear to be too late in the season or too early in the previous year to affect ring width. We recommend that this x² technique be added to the existing dendroclimatic procedures because it reveals many more possible cause and effect relationships.
23
Gayle, Suelen S. "A simulation study of the size and power of Cochran’s Q versus the standard Chi-square test for testing the equality of correlated proportions." Kansas State University, 2010. http://hdl.handle.net/2097/3881.
Full textAbstract:
Master of Science<br>Department of Statistics<br>Paul I. Nelson<br>The standard Chi-square test for the equality of proportions of positive responses to c
specified binary questions is valid when the observed responses arise from independent random
samples of units. When the responses to all c questions are recorded on the same unit, a situation
called correlated proportions, the assumptions under which this test is derived are no longer
valid. Under the additional assumption of compound symmetry, the Cochran-Q test is a valid
test for the equality of proportions of positive responses. The purpose of this report is to use
simulation to examine and compare the performance of the Cochran-Q test and the standard Chisquare
test when testing for the equality of correlated proportions. It is found that the Cochran-Q
test is superior to the Chi-square test in terms of size and power, especially when the common
correlation among the binary responses is large.
24
Horttana, Jonas. "Real Estate Forecasting – An evaluation of forecasts." Thesis, KTH, Fastigheter och byggande, 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-124002.
Full textAbstract:
This degree project aims to explore the subject of forecasting, which is an ongoing and much alive debate within economics and finance. Within the forecasting field the available research is vast and even if restricted to real estate, which is the main focus of this paper, the available material is comprehensive. A large fraction of published research concerning the subject of real estate forecasting consists of post mortem studies, with econometric models trying to replicate historical trends with the help of available micro and macro data. This branch within the field of forecasting seems to advance and progress with help of refined econometric models. This paper, on the other hand, rather examines the fundamentals behind forecasting and why forecasting can be a difficult task in general. This is shown with an examination of the accuracy of 160 unique forecasts within the field of real estate. To evaluate the accuracy and predictability from different perspectives we state three main null hypotheses: 1. Correct forecasts and the direction of the predictions are independent variables. 2. Correct forecasts and the examined consultants are independent variables. 3. Correct forecasts and the examined cities are independent variables. 4 The observed frequencies for Hypothesis 1 indicate that upward predictions seem to be easier to predict than downward predictions. This is however not supported by the statistical tests. The observed frequencies for Hypothesis 2 clearly indicate that one consultant is a superior forecaster than compared to the other consultants. The statistical tests confirm this. The observed frequencies for Hypothesis 3 indicate no signs of dependence for the variables. The statistical tests confirm this.<br>Detta examensarbete ämnar att utforska ämnesområdet kring prognoser och prognosmakande, vilket är en högst levande debatt inom ekonomi och finans. Inom detta område är tillgänglig forskning mycket omfattande och även om materialet begränsas till fastighetsmarknaden, som är huvudspåret i denna uppsats, är mängden information ansenlig. En stor andel av publicerad forskning som berör prognoser av fastighetsmarkanden består ofta av studier av typen "post mortem", där man med ekonometriska modeller försöker efterlikna tidigare historiska trender med hjälp av tillgänglig mikro- eller makrodata. Denna gren av forskningen tycks vinna mark och fortsätter att utvecklas med hjälp av allt mer avancerade ekonometriska modeller. Denna studie fokuserar däremot snarare på de fundamentala elementen av prognosmakande och varför detta ibland kan vara en problematisk uppgift. Detta visas med hjälp av en undersökning gällande utfallet och träffsäkerheten av 160 unika prognoser på fastighetsmarknaden. 7 För att utvärdera träffsäkerheten hos prognoserna sätts tre olika nollhypoteser upp: 1. Korrekt prognos och riktning av prognos är oberoende variabler. 2. Korrekt prognos och konsult är oberoende variabler. 3. Korrekt prognos och undersökta städer är oberoende variabler. De observerade frekvenserna för Hypotes 1 indikerar att uppåtgående prognoser är enklare att förutspå än övriga prognoser. Detta kan dock inte stödjas av de statistiska testerna. De observerade frekvenserna för Hypotes 2 indikerar tydligt att en konsult är en överlägsen prognosmakare än övriga konsulter. Detta stöds av de statistiska testerna. De observerade frekvenserna för Hypotes 3 indikerar inget samband av beroende mellan variablerna. Detta kan dock inte stödjas av de statistiska testerna.
25
Wu, Baohua. "Data Driven Approaches to Testing Homogeneity of Intraclass Correlation Coefficients." Digital Archive @ GSU, 2010. http://digitalarchive.gsu.edu/math_theses/92.
Full textAbstract:
The test of homogeneity for intraclass correlation coefficients has been one of the active topics in statistical research. Several chi-square tests have been proposed to test the homogeneity of intraclass correlations in the past few decades. The big concern for them is that these methods are seriously biased when sample sizes are not large. In this thesis, data driven approaches are proposed to testing the homogeneity of intraclass correlation coefficients of several populations. Through simulation study, data driven methods have been proved to be less biased and accurate than some commonly used chi-square tests.
26
ERIC, AIDOO, and ZHENG SAIJING. "HAPPINESS INDEXTHE CONSTRUCTION AND ANALYSIS." Thesis, Högskolan Dalarna, Statistik, 2010. http://urn.kb.se/resolve?urn=urn:nbn:se:du-4853.
Full textAbstract:
This study aims to investigate the important indicators that contribute to happiness among Beijing residence. The residents of Beijing were taken as the target population for the survey. A questionnaire was used as the main statistical instrument to collect the data from the residents in Beijing. In so doing the investigation employs Factor analyses and chi-square analyses as the main statistical tools used for the analyses in this research. The study found that Beijing residents gained greater happiness in the family, interpersonal relationships, and health status. The analysis also shows that generally, the residence of Beijing feels happier and also in terms of gender basis, females in Beijing feel happier as compare to their male counterpart. It will find that gender, age and education are statistically significant when dealing with happiness.
27
Tran, Vuong, and Sebastian Öhgren. "Analys av kvalitet i en webbpanel : Studie av webbpanelsmedlemmarna och deras svarsmönster." Thesis, Linköpings universitet, Statistik, 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-95456.
Full textAbstract:
During 2012, the employer of this essay carried out a telephone survey with 18000 participants and a web panel survey with 708 participants. Those who partook in the telephone survey were given a choice to join the web panel. The purpose of this work is to study the participants of the telephone survey and see if they reflect the Swedish population with regards to several socio-demographic factors. Also, we intend to investigate if the propensity to join the web panel differs for participants of the telephone survey with regards to various socio-demographic affiliations. It is also of interest to study if the response pattern is different for participants of the telephone survey that would like to join the web panel and those who reject. A comparison of response pattern between the telephone survey and web panel survey has also been done, to see if there exist any differences for these two groups of surveys. The statistical methods used in this essay are descriptive statistics, multiple logistic regression and decision trees. Conclusions to be drawn with result from these methods are that the participants from the telephone survey do reflect the Swedish population regarding certain socio-demographic factors and that there is a slight difference in propensity to join the web panel for people which have dissimilar socio-demographic affiliation. It has also been found that there is a slight difference in response pattern for participants who would or would not like to join the web panel, as well as differences in response pattern also exist between the telephone survey and the web panel survey.
28
Li, Rong. "A Tree-based Framework for Difference Summarization." Kent State University / OhioLINK, 2012. http://rave.ohiolink.edu/etdc/view?acc_num=kent1334277940.
Full text
29
Huang, Hesha, Mengwei Jiang, and Fan Liu. "Water Pollution in China : study on the relationship between economic development and water pollution." Thesis, Högskolan Kristianstad, Sektionen för hälsa och samhälle, 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:hkr:diva-10861.
Full textAbstract:
Purpose/aim The purpose of the research is to analyze the relationship between water pollution (WP) and the economic development in China. We found a vicious cycle that at the same time as China’s economy has developed; the WP has become the focus of attention, and has also caused huge economic losses. Faced with this situation, this topic is really worth to study. Design/methodology/approach The research adopted a quantitative methodology for the exploration, and conducted a survey through questionnaires which were answered by different people. These respondents come from four areas in China. After having conducted the survey, we selected three typical provinces as representative for each area, and surveyed the basic information about these places. The sample information was calculated by the Chi-square test. The results will be analyzed together with the findings below. Findings The findings indicated that through an analysis of GDP, population, the economic development level and the degree of WP, there is relationship between economic development and WP. When people ignore the problem of WP, and just focus on the economy, the relationship shows that the more developing of economy, the more serious the WP becomes. Originality/value The original idea in our dissertation is to discuss the relationship between economic development and WP in China. The water problem and economic development form a vicious circle. And it seriously affects the whole China. The study has a value for the improvement of the environmental awareness of all the people in China, and advocates the government to develop the economy, and at the same time protect the water sources.
30
Tao, Jinxin. "Comparison Between Confidence Intervals of Multiple Linear Regression Model with or without Constraints." Digital WPI, 2017. https://digitalcommons.wpi.edu/etd-theses/404.
Full textAbstract:
Regression analysis is one of the most applied statistical techniques. The sta- tistical inference of a linear regression model with a monotone constraint had been discussed in early analysis. A natural question arises when it comes to the difference between the cases of with and without the constraint. Although the comparison be- tween confidence intervals of linear regression models with and without restriction for one predictor variable had been considered, this discussion for multiple regres- sion is required. In this thesis, I discuss the comparison of the confidence intervals between a multiple linear regression model with and without constraints.
31
Gayle, Suelen S. "A simulation study of the size and power of Cochran's Q versus the standard Chi-square test for testing the equality of correlated proportions." Manhattan, Kan. : Kansas State University, 2010. http://hdl.handle.net/2097/3881.
Full text
32
Monaco, Linda Gokey. "A Comparison of Three Methods of Detecting Test Item Bias." Thesis, North Texas State University, 1985. https://digital.library.unt.edu/ark:/67531/metadc331416/.
Full textAbstract:
This study compared three methods of detecting test item bias, the chi-square approach, the transformed item difficulties approach, and the Linn-Harnish three-parameter item response approach which is the only Item Response Theory (IRT) method that can be utilized with minority samples relatively small in size. The items on two tests which measured writing and reading skills were examined for evidence of sex and ethnic bias. Eight sets of samples, four from each test, were randomly selected from the population (N=7287) of sixth, seventh, and eighth grade students enrolled in a large, urban school district in the southwestern United States. Each set of samples, male/female, White/Hispanic, White/Black, and White/White, contained 800 examinees in the majority group and 200 in the minority group. In an attempt to control differences in ability that may have existed between the various population groups, examinees with scores greater or less than two standard deviations from their group's mean were eliminated. Ethnic samples contained equal numbers of each sex. The White/White sets of samples were utilized to provide baseline bias estimates because the tests could not logically be biased against these groups. Bias indices were then calculated for each set of samples with each of the three methods. Findings of this study indicate that the percent agreement between the Linn-Harnish IRT method and the chisquare and transformed difficulties methods is similar to that found in previous studies comparing the latter approaches with other IRT methods requiring large minority samples. Therefore, it appears that the Linn-Harnish IRT approach can be used in lieu of other more restrictive IRT methods. Ethnic bias appears to exist in the two tests as measured by the large mean bias indices for the White/Hispanic and White/Black samples. Little sex bias was found as evidenced by the low mean bias indices of the male/ female samples and the fact that the male/female mean bias indices were lower than those of the White/White in 33% of the samples.
33
Chen, Xinyu. "Inference in Constrained Linear Regression." Digital WPI, 2017. https://digitalcommons.wpi.edu/etd-theses/405.
Full textAbstract:
Regression analyses constitutes an important part of the statistical inference and has great applications in many areas. In some applications, we strongly believe that the regression function changes monotonically with some or all of the predictor variables in a region of interest. Deriving analyses under such constraints will be an enormous task. In this work, the restricted prediction interval for the mean of the regression function is constructed when two predictors are present. I use a modified likelihood ratio test (LRT) to construct prediction intervals.
34
Zhang, Yan. "The impact of midbrain cauterize size on auditory and visual responses' distribution." unrestricted, 2009. http://etd.gsu.edu/theses/available/etd-04202009-145923/.
Full textAbstract:
Thesis (M.S.)--Georgia State University, 2009.<br>Title from file title page. Yu-Sheng Hsu, committee chair; Xu Zhang, Sarah. L. Pallas, committee members. Description based on contents viewed June 12, 2009. Includes bibliographical references (p. 37). Appendix A: SAS code: p. 38-53.
35
Yan, Lu. "Risk Management Project." Digital WPI, 2012. https://digitalcommons.wpi.edu/etd-theses/648.
Full textAbstract:
In order to evaluate and manage portfolio risk, we separated this project into three sections. In the first section we constructed a portfolio with 15 different stocks and six options with different strategies. The portfolio was implemented in Interactive Brokers and rebalanced weekly through five holding periods. In the second section we modeled the loss distribution of the whole portfolio with normal and student-t distributions, we computed the Value-at-Risk and expected shortfall in detail for the portfolio loss in each holding week, and then we evaluated differences between the normal and student-t distributions. In the third section we applied the ARMA(1,1)-GARCH(1,1) model to simulate our assets and compared the polynomial tails with Gaussian and t-distribution innovations.
36
Shen, Chen. "Risk Management Project." Digital WPI, 2012. https://digitalcommons.wpi.edu/etd-theses/650.
Full textAbstract:
In order to evaluate and manage portfolio risk, we separated this project into three sections. In the first section we constructed a portfolio with 15 different stocks and six options with different strategies. The portfolio was implemented in Interactive Brokers and rebalanced weekly through five holding periods. In the second section we modeled the loss distribution of the whole portfolio with normal and student-t distributions, we computed the Value-at-Risk and expected shortfall in detail for the portfolio loss in each holding week, and then we evaluated differences between the normal and student-t distributions. In the third section we applied the ARMA(1,1)-GARCH(1,1) model to simulate our assets and compared the polynomial tails with Gaussian and t-distribution innovations.
37
Beirowski, Karin. "Cultural influences on attitudes toward aggression : a comparison between Spanish, Japanese and South African students." Thesis, Stellenbosch : Stellenbosch University, 2003. http://hdl.handle.net/10019.1/53341.
Full textAbstract:
Thesis (MA)--University of Stellenbosch, 2003.<br>ENGLISH ABSTRACT: The primary aim of the present study was to examine whether the culture of a society influences
the way in which people justify certain aggressive behaviours in certain situations. A total of 756
students from Spain, Japan and South Africa participated in completing the CAMA, a measure of
justification of aggression. The results showed that there were significant differences within the
countries. There were differences in the levels of acceptance of certain acts between these
countries. Further fmdings also indicated that there was a difference between the males of the
countries and between the females of these countries. It was found that cultural influences and
the norms within these countries bring about differences in justification of aggression in different
situations. There were also some general trends of acceptance, with direct and indirect verbal
acts e.g. sarcasm, hindering and shouting being more acceptable than physical acts such as
hitting, killing and torture. It is hoped that the present findings of this research will make
members of society more aware of their responsibility to help reduce aggressive acts by teaching
and reinforcing norms against it. It is also hoped that the international community will gain better
insight into the fact that South-Africa faces unique challenges because of the political and social
changes in the country.<br>AFRIKAANSE OPSOMMING: Die primêre doel van die huidige studie was om vas te stelof 'n samelewing se kultuur 'n rol
speel by die regverdiging van sekere aggressiewe gedrag in bepaalde omstandighede. 'n Totaal
van 756 studente van Spanje, Japan en Suid Afrika het die CAMA vraelys voltooi. Die vraelys
meet die regverdiging van aggressie in sekere omstandighede. Betekenisvolle verskille is tussen
die lande gevind. Daar is ook betekenisvolle verskille tussen die mans van die drie lande asook
tussen die vrouens van die drie lande gevind. Daar is gevind dat kulturele verskille en die norme
binne 'n samelewing meebring dat daar verskille is in die mate waarin samelewings sekere
aggressiewe gedrag aanvaarbaar vind in sekere situasies. Daar was ook 'n groter algemene
aanvaarbaarheid van verbale aggressie bv. sarkasme, verhindering en skreeu as fisiese aggressie
soos slaan, om dood te maak en marteling. Hopelik maak hierdie navorsing mense meer bewus
van elkeen in die samelewing se verantwoordelikheid om die norme teen geweld te versterk
asook om die norme aan hulle nageslagte oor te dra. Verder sal die internasionale gemeenskap
hopelik beter insig kry oor die unieke uitdagings wat Suid-Afrika bied as gevolg van die
politieke en sosiale veranderinge in die land.
38
Hosseini, Reyhaneh. "New Developments on Bayesian Bootstrap for Unrestricted and Restricted Distributions." Thesis, Université d'Ottawa / University of Ottawa, 2019. http://hdl.handle.net/10393/39110.
Full textAbstract:
The recent popularity of Bayesian inference is due to the practical advantages of the Bayesian approach. The Bayesian analysis makes it possible to reflect ones prior
beliefs into the analysis. In this thesis, we explore some asymptotic results in Bayesian nonparametric inference for restricted and unrestricted space of distributions. This thesis is divided into two parts. In the first part, we employ the Dirichlet process in a hypothesis testing framework to propose a Bayesian nonparametric chi-squared goodness-of-fit test. Our suggested method corresponds to Lo's Bayesian bootstrap procedure for chi-squared goodness-of-fit test. Indeed, our bootstrap rectifies some shortcomings of regular bootstrap which only counts number of observations falling in each bin in contingency tables. We consider the Dirichlet process as the prior for the distribution of data and carry out the test based on the Kullback-Leibler distance between the Dirichlet process posterior and the hypothesized distribution. We prove that this distance asymptotically converges to the same chi-squared distribution as the classical frequentist's chi-squared test. Moreover, the results are generalized to the chi-squared test of independence for contingency tables. In the second part, our main focus is on Bayesian nonparametric inference for
a restricted group of distributions called spherically symmetric distributions. We describe a Bayesian nonparametric approach to perform an inference for a bivariate spherically symmetric distribution. We place a Dirichlet invariant process prior on the set of all bivariate spherically symmetric distributions and derive the Dirichlet invariant process posterior. Indeed, our approach is an extension of the Dirichlet invariant process for the symmetric distributions on the real line to bivariate spherically symmetric distribution where the underlying distribution is invariant under a finite group of rotations. Further, we obtain the Dirichlet invariant process posterior for the infinite transformation group and we prove that it approaches a certain Dirichlet process. Finally, we develop our approach to obtain the Bayesian nonparametric posterior distribution for functionals of the distribution's support when the support satisfies certain symmetry conditions. When symmetry holds with respect to the parallel lines of axes (for example, in two dimensional space x = a and y = b) we employ our approach to approximate the distribution of certain functionals such as area and perimeter for the support of the distribution. This suggests a Bayesian nonparametric bootstrapping scheme. The estimates can be derived based on posterior averaging. Then, our simulation results demonstrate that our suggested bootstrapping technique improves the accuracy of the estimates.
39
Lynch, O'Neil. "Mixture distributions with application to microarray data analysis." Scholar Commons, 2009. http://scholarcommons.usf.edu/etd/2075.
Full textAbstract:
The main goal in analyzing microarray data is to determine the genes that are differentially expressed across two types of tissue samples or samples obtained under two experimental conditions. In this dissertation we proposed two methods to determine differentially expressed genes. For the penalized normal mixture model (PMMM) to determine genes that are differentially expressed, we penalized both the variance and the mixing proportion parameters simultaneously. The variance parameter was penalized so that the log-likelihood will be bounded, while the mixing proportion parameter was penalized so that its estimates are not on the boundary of its parametric space. The null distribution of the likelihood ratio test statistic (LRTS) was simulated so that we could perform a hypothesis test for the number of components of the penalized normal mixture model. In addition to simulating the null distribution of the LRTS for the penalized normal mixture model, we showed that the maximum likelihood estimates were asymptotically normal, which is a first step that is necessary to prove the asymptotic null distribution of the LRTS. This result is a significant contribution to field of normal mixture model.
The modified p-value approach for detecting differentially expressed genes was also discussed in this dissertation. The modified p-value approach was implemented so that a hypothesis test for the number of components can be conducted by using the modified likelihood ratio test. In the modified p-value approach we penalized the mixing proportion so that the estimates of the mixing proportion are not on the boundary of its parametric space. The null distribution of the (LRTS) was simulated so that the number of components of the uniform beta mixture model can be determined. Finally, for both modified methods, the penalized normal mixture model and the modified p-value approach were applied to simulated and real data.
40
Sacks, William Andrew. "Healthcare providers' experience of chronic grief in a pediatric subacute facility." CSUSB ScholarWorks, 2001. https://scholarworks.lib.csusb.edu/etd-project/2034.
Full textAbstract:
The purpose of this study was: (1) to evaluate the level of grief experienced by healthcare providers in a pediatric subacute facility, (2) to compare the levels of grief between different groups of healthcare providers (Certified Nurses' Aides, Licensed Nurses, and Respiratory Care Practitioners), and (3) to describe the personality/demographic factors that influence a healthcare provider's ability to cope effectively with compound grief.
41
Röjdén, Thyberg Sandra, and Mélica Gabrielsson. "ASI-Intervjun : en explorativ studie av samband och grupperingar." Thesis, Linköpings universitet, Statistik, 2010. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-69740.
Full textAbstract:
Med en explorativ ansats syftar denna studie till att kartlägga samband och jämföra grupperingar bland klienter som fått genomföra en ASI-intervju hos Kriminalvården. Studien bygger på 2 317 intervjuer med fokus på missbruksproblematik, gjorda under perioden 2008-2010. Vi illustrerar grafiskt intressanta samband och tittar även på hur klienternas hjälpbehov varierar inom olika livsområden. Ytterligare en aspekt av studien är att utvärdera datamaterialets kvalitet samt att studera eventuellt bortfall för de olika variablerna. Materialet är av relativt god kvalitet och förekomst av respondenters vägran är inte tillräckligt omfattande för att påverka analyser och slutsatser. De felaktigheter som kunde konstateras härhör nästan uteslutande från tillvägagångssätt vid inmatning av data i systemet. Eftersom flertalet av variablerna är kvalitativa visade sig lämpliga analysmetoder vara chi-två-test, korrespondensanalys samt associationsanalys. Den stora majoriteten av våra resultat bekräftar den bild flera tidigare studier ger av gruppen missbrukare och få oväntade samband kunde konstateras. En majoritet av klienterna är män (85%) och den genomsnittliga åldern är 34 år. Intervjuarskattningar av klienternas hjälpbehov visar att narkotika och kriminalitet utgör de absolut största problemen. Dominerande drog är amfetamin (18%), följd av alkohol (15%) och cannabis (10%). Vi kan konstatera att ett flertal signifikanta skillnader föreligger mellan män och kvinnor samt mellan olika åldersgrupper. Unga klienter uppvisar överlag större problem med kriminalitet, narkotika, arbete/försörjning och psykisk hälsa. Med ökande ålder följer istället svårigheter med fysisk hälsa och alkohol. Män uppger vanligen att de har större problem med kriminalitet och narkotika, medan kvinnor ofta redovisar ett större hjälpbehov inom områdena familj/umgänge, fysisk hälsa och psykisk hälsa.<br>With an explorative approach, this master thesis attempts to map associations and compare groupings of clients who have undergone an ASI Interview by The Swedish Prison and Probation Service, Kriminalvården. The study is based on 2 317 interviews carried out during the period 2008-2010, focusing on abuse of alcohol and narcotic substances. We will graphically illustrate interesting associations and study how the need for help varies throughout different areas of the respondents’ lives. Another aspect of this study is to evaluate the quality of the data material and to investigate non-response in the different variables. The quality of the material is fairly high and non-response is not extensive enough to affect analysis and inference. The errors found are almost exclusively due to how data is fed into the system. Since the majority of variables are qualitative, appropriate methods of analysis proved to be chi-square tests, correspondence analysis and association analysis. Most results confirm the existing image of an abusive personality, which has been presented in several studies before this one. A majority of the clients are men (85%) and the average age is 34 years. Interviewer estimates of the respondents’ need for help show that narcotic substances and criminal behavior are by far the greatest problem areas. The predominant drug is amphetamine (18%), followed by alcohol (15%) and cannabis (10%). We have established several significant differences between men and women, and between clients of different age groups. Young respondents show greater problems concerning criminal behavior, narcotic substances, work/providing and psychological health. With increased age we see enhanced difficulties regarding physical health and alcohol. Men more often exhibit problems concerning criminal behavior and narcotic substances, while women need increased help in areas of family/social life, physical health and psychological health.
42
Belen, Rahime. "Detecting Disguised Missing Data." Master's thesis, METU, 2009. http://etd.lib.metu.edu.tr/upload/12610411/index.pdf.
Full textAbstract:
In some applications, explicit codes are provided for missing data such as NA (not available) however many applications do not provide such explicit codes and valid or invalid data codes are recorded as legitimate data values. Such missing values are known as disguised missing data. Disguised missing data may affect the quality of data analysis negatively, for example the results of discovered association rules in KDD-Cup-98 data sets have clearly shown the need of applying data quality management prior to analysis. In this thesis, to tackle the problem of disguised missing data, we analyzed embedded unbiased sample heuristic (EUSH), demonstrated the methods drawbacks and proposed a new methodology based on Chi Square Two Sample Test. The proposed method does not require any domain background knowledge and compares favorably with EUSH.
43
Araújo, Mirian Fernandes Carvalho. "Teste estatístico para contribuição de genótipos e ambientes na matriz de interação GE." Universidade de São Paulo, 2008. http://www.teses.usp.br/teses/disponiveis/11/11134/tde-07082008-124513/.
Full textAbstract:
O presente trabalho teve por objetivos propor um método para testar a contribuição de cada genótipo e ambiente para a interação genótipos X ambientes em ensaios multi-ambientais através de um teste F e implementar uma rotina computacional para a realização da análise de dados segundo o teste proposto. O estudo avalia quatro conjuntos de dados, cada um com diferentes números de genótipos dentro de ambientes com quatro blocos. Para um dos conjuntos, simulou-se as somas de quadrados das linhas (genótipos) e colunas (ambientes) da matriz de interação genótipos X ambientes (GE) gerando 500, 5000 e 10000 experimentos para verificar a distribuição empírica. Os resultados indicaram um ajuste à distribuição qui-quadrado não-central para as linhas e colunas da matriz de interação GE, verificados também pelo teste de Kolmogorov-Smirnov e o gráfico QQplot. Na aplicação do teste F proposto aos quatro conjuntos de dados, identificou-se os genótipos e ambientes que contribuiram mais para a interação genótipos X ambientes. Dessa forma, os melhoristas podem selecionar bons genótipos e ambientes nos seus estudos.<br>The objective of the present work was to propose a method for testing the con- tribution of each element in a genotypes X environments interaction using multi-environment analyses by means of an F test and implementation of a computational routine to analyze the data according to the test proposed. The study evaluated four data sets, each with a di®erent number of genotypes and environments, in a block design with four repetitions. In one group, the sum of squares within rows (genotypes) and columns (environments) of the genotypes X environments (GE) matrix was simulated, generating 500, 5000 and 10000 experiments to verify the empirical distribution. Results indicate a non-central chi-squared distribution for rows and columns of the GE interaction matrix, which was also verified by the Kolmogorov-Smirnov test and QQplot graph. Application of the F test to the four data sets identified the genotypes and environments that contributed the most to the genotypes X environments interaction. In this way, geneticists can select good genotypes and environments in their studies.
44
Viking, Jakob. "Identifying Machine States and Sensor Properties for a Digital Machine Template : Automatically recognize states in a machine using multivariate time series cluster analysis." Thesis, Mittuniversitetet, Institutionen för informationssystem och –teknologi, 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:miun:diva-42295.
Full textAbstract:
Digital twins have become a large part of new cyber-physical systems as they allow for the simulation of a physical object in the digital world. In addition to the new approaches of digital twins, machines have become more intelligent, allowing them to produce more data than ever before. Within the area of digital twins, there is a need for a less complex approach than a fully optimised digital twin. This approach is more like a digital shadow of the physical object. Therefore, the focus of this thesis is to study machine states and statistical distributions for all sensors in a machine. Where as majority of studies in the literature focuses on generating data from a digital twin, this study focuses on what characteristics a digital twin have. The solution is by defining a term named digital machine template that contains the states and statistical properties of each sensor in a given machine. The primary approach is to create a proof of work application that uses traditional data mining technologies and clustering to analyze how many states there are in a machine and how the sensor data is structured. It all results in a digital machine template with all of the information mentioned above. The results contain all the states a machine might have and the possible statistical distributions of each senor in each state. The digital machine template opens the possibility of using it as a basis for creating a digital twins. It allows the time of development to be shorter than that of a regular digital twin. More research still needs to be done as the less complex approach may lead to missing information or information not being interpreted correctly. It still shows promises as a less complex way of looking at digital twins since it may become necessary due to digital twins becoming even more complex by the day.
45
Lam, Sean Hon Wai. "A rubric based approach towards Automated Essay Grading : focusing on high level content issues and ideas." Thesis, Curtin University, 2012. http://hdl.handle.net/20.500.11937/38.
Full textAbstract:
Assessment of a student’s work is by no means an easy task. Even if the student response is in the form of multiple choice answers, manually marking those answer sheets is a task that most teachers regard as rather tedious. The development of an automated method to grade these essays was thus an inevitable step.This thesis proposes a novel approach towards Automated Essay Grading through the use of various concepts found within the field of Narratology. Through a review of the literature, several methods in which essays are graded were identified together with some of the problems. Mainly, the issues and challenges that plague AEG systems were that those following the statistical approach needed a way to deal with more implicit features of free text, while other systems which did manage that were highly dependent on the type of student response, the systems having pre-knowledge pertaining to the subject domain in addition to requiring more computational power. It was also found that while narrative essays are one of the main methods in which a student might be able to showcase his/her mastery over the English language, no system thus far has attempted to incorporate narrative concepts into analysing these type of free text responses.It was decided that the proposed solution would be centred on the detection of Events, which was in turn used to determine the score an essay receives under the criteria of Audience, Ideas, Character and Setting and Cohesion, as defined by the NAPLAN rubric. From the results gathered from experiments conducted on the four criteria mentioned above, it was concluded that the concept of detecting Events as they were within a narrative type story when applied to essay grading, does have a relation towards the score the essay receives. All experiments achieved an average F-measure score of 0.65 and above while exact agreement rates were no lower than 70%. Chi-squared and paired T-test values all indicated that there was insufficient evidence to show that there was any significant difference between the scores generated by the computer and those of the human markers.
46
Bolesworth, Karen, and Susan Tufts. "Social welfare policy and the crisis of hunger." CSUSB ScholarWorks, 2001. https://scholarworks.lib.csusb.edu/etd-project/1891.
Full textAbstract:
The Personal Responsibility and Work Opportunity Reconciliation Act of 1996 has lead to reduced welfare assistance to the needy. This thesis analyzes how families have become increasingly homeless and hungry during the welfare reform years.
47
'Malebese, Mot'selisi Lilian. "The relationship between parental support and self-regulated learning behavior of Grade 12 learners in Lejweleputswa." Thesis, [Bloemfontein?] : Central University of Technology, Free State, 2013. http://hdl.handle.net/11462/183.
Full textAbstract:
Thesis (M. Education) -- Central University of Technology, Free State, 2013<br>The purpose of the study was to investigate the relationship between parental support and self-regulated learning behaviour of grade 12 learners. The study investigated support given to self-regulated learning of grade 12 learners. It gathered both quantitative and qualitative data. The researcher adopted the QUAN-qual model, which is also known as explanatory design. In this model quantitative data are collected first and are more heavily weighted than qualitative data.
The quantitative method investigated the relationship between parental support and grade 12 learners’ self-regulated learning behaviour. It also investigated how parental support contributed to learner self-regulated learning behaviour. Qualitative research design explained strategies schools used to encourage positive parental support in their children’s self-regulated learning. It also explained why parents did not offer their support to their children’s education despite the fact that the South African School Act of 1996 encouraged them to do so.
The population included grade 12 teachers and learners, as well as learners’ parents from different secondary schools in the Lejweleputswa district. The researcher administered questionnaires to 118 teachers and 218 learners, while 6 parents were interviewed. Teachers and learners were handed relevant questionnaires aimed at their level of participation in the survey. For quantitative data analysis the chi-square test was employed to test whether there were relationships between the variables. The study revealed that there was statistical significant relationship between parental support and learners’ self-regulated learning behaviour. Qualitative data was analysed making use of different analytical concepts used to guide researchers in qualitative data analysis. Although learners may acquire effective self-regulated learning strategies on their own, proper guidance from parents and teachers is very crucial, especially in the early stages of learning. The study established that regular general parent’s meetings, each term, help to facilitate improved learner performance. Amongst others, the researcher recommended that schools should introduce incentive for parental involvement in school matters.
48
Urbánková, Kateřina. "Motivační faktory poctivého daňového přiznání." Master's thesis, Vysoká škola ekonomická v Praze, 2015. http://www.nusl.cz/ntk/nusl-205772.
Full textAbstract:
The diploma thesis deals with the motivation factors of a rightful tax return. The aim of the thesis was to identify influence of attitude, subjective norms and behavioural control on a truthfulness of a taxpayer when filling in the tax return. The first part of the thesis is aimed on definition of a tax evasion. Furthermore, this part deals with the causes of tax evasions as well as with ethical point of view on tax evasions in general. The second part of the thesis deals with the indicators of extent and evolution of tax evasions in the Czech Republic and in the European Union. The indicators of tax evasions are the following: shadow economy, tax gap of VAT, tax quota, corruption index and frequency of tax control. The third part includes the results of the questionnaire survey that was realised among the Czech entrepreneurs. The results show the cases of tax evasions that the entrepreneurs may have consider as rightful. Thereafter, using the chi-squared test, the analysis examined whether the attitude of the entrepreneurs towards the tax evasions is influenced by the factors as company seat, annual turnover or number of employees. In several cases, the research confirmed an existence of dependence between attitude of entrepreneurs towards tax evasions and the factors stated above.
49
Ščerbakov, Jaroslav. "Statistinių hipotezių taikymas mokomųjų kompiuterių priemonių naudojimo matematikos pamokose analizei." Master's thesis, Lithuanian Academic Libraries Network (LABT), 2005. http://vddb.library.lt/obj/LT-eLABa-0001:E.02~2005~D_20050622_131057-36373.
Full textAbstract:
The research is dealing with the problem of choosing right statistical criteria in order to analyze the concrete educological research information and to interpret the received results. The practical value of the research’s results could be described as: 1- the exact evaluation of the real situation, by researching the effectiveness of use of educational computer means at the lessons of mathematics, with the help of hypothesises; 2- the statistical criteria received at the time of the research can be used at the concrete future researches.
50
Sheen, Peter Bernard. "Managing Intellectual Property and Licensing: A Study on Cooperative Research Centres." Thesis, Queensland University of Technology, 2005. https://eprints.qut.edu.au/16010/1/Peter_Sheen_Thesis.pdf.
Full textAbstract:
This thesis examines the perceived importance by two-tiered management of Cooperative Research Centres (CRCs) for managing a range of intellectual property issues. Fifty survey items are presented to the executive directors and
commercialization managers of 62 CRCs. The survey items are categorized under four themes: relationships with collaborators, project management; design and implementation of agreements; and specific licensing issues. An analysis of the data, using a series of independent samples t-tests, repeated measures t-tests, chi-square tests for independence or relatedness and goodness of fit, shows a range of results. There are significant differences between executive directors and commercialization
managers on a number of issues. There are particular emphases or trends about certain issues for the whole sample of managers.
These findings are compared with text analyses of 23 CRC strategic planning documents. This is done in order to explore any similarity, difference or nuance between what the managers say in response to the survey items, compared with what is stated in the codified policies of the CRCs. While there is a high degree of
consistency among certain themes between the two sets of findings, the overall analysis points to the need for the CRCs to have a better understanding and practice of commercialization opportunities, especially through the involvement of third party commercial interests. It is argued that accommodating third party commercialization interests involves the application of an important knowledge economy principle that has an important bearing on the future economic viability and competitiveness of the CRCs.