Kliknij ten link, aby zobaczyć inne rodzaje publikacji na ten temat: Statistics Norway.
Rozprawy doktorskie na temat „Statistics Norway”
Utwórz poprawne odniesienie w stylach APA, MLA, Chicago, Harvard i wielu innych
Sprawdź 50 najlepszych rozpraw doktorskich naukowych na temat „Statistics Norway”.
Przycisk „Dodaj do bibliografii” jest dostępny obok każdej pracy w bibliografii. Użyj go – a my automatycznie utworzymy odniesienie bibliograficzne do wybranej pracy w stylu cytowania, którego potrzebujesz: APA, MLA, Harvard, Chicago, Vancouver itp.
Możesz również pobrać pełny tekst publikacji naukowej w formacie „.pdf” i przeczytać adnotację do pracy online, jeśli odpowiednie parametry są dostępne w metadanych.
Przeglądaj rozprawy doktorskie z różnych dziedzin i twórz odpowiednie bibliografie.
1
Öhman, Camilla. "Sports Facility Statistics : Overview of built sports facilities and analysis of sports hall costs in Norway". Thesis, Uppsala universitet, Matematiska institutionen, 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-301508.
Pełny tekst źródłaStreszczenie:
The current statistics on sports facilities suggests that 4 billion NOK (divided on 700 facilities) are planned to be used annually for new sports facility projects and renovation projects of old sports facilities. These statistics are based on planned projects and not on realized projects. In addition, it is not distinguished between new facility projects and facility renovation projects. The current statistics is based on applications for so-called gaming funds, which are all registered in a sports facilities information system. The information system is complicated to use, and the data in the register is not perfect: it is inconsistent and sometimes incorrect or incomplete. This thesis provides an overview of the number of built sports facilities in Norway between 1996 and 2016. Further, it provides cost statistics for sports halls, based on extracted data from the information system, which was preprocessed and then analyzed using regression models and ANOVA. This work shows that, in average, 560 sports facilities have been built each year between 1996 and 2015 (1 000 facilities if one includes so-called local activity facilities). In average 24 sports halls have been built each year, with an average cost of 36 million NOK. Sports halls built in Oslo have in average costed 14 to 23 million NOK more to build than sports halls in the rest of Norway.
2
Berg, Christian. "The ever increasing use of acid suppressive therapy : Descriptive analysis of data from the national wholesale and prescription databases on the consumption of proton pump inhibitor in Norway". Thesis, Nordic School of Public Health NHV, 2007. http://urn.kb.se/resolve?urn=urn:nbn:se:norden:org:diva-3223.
Pełny tekst źródłaStreszczenie:
Pharmacoepidemiological analyses are needed as a background for evaluation of drug use and for making cost-effective priorities. Drug sales and prescription databases provide useful tools for analysis of drug consumption and expenditures. In this essay, an analysis of the sales and prescribing of proton pump inhibitors (PPIs), drugs used for acid related gastric disorders, are presented. Since 1996, the consumption of PPIs in Norway has increased by approximately 10 % per year, with esomeprazole as the most commonly used drug. An increasing number of individuals are using these drugs with considerable costs for the reimbursement schemes, e.g., in 2006 more than 450 million NOK. Verified reflux oesophagitis is the predominant indication for reimbursement prescribing. There are, however, indications of an overprescribing of PPIs. The prescribing in Norway is different from Denmark and Sweden, both regarding choice of drug and level of consumption. The prevalence of PPI use increased with age, reaching a maximum of nearly 12 % in the age groups 70-79 and 80-89 years of age. A considerable proportion is long-term users (> 2 years). These groups have a high risk of polypharmacy treatment. Even though the PPIs have been on the market for many years, negative effects associated with long term use are being discussed and need to be further explored. Attention should be focused on the rational use of PPIs and not only on the reduction of costs for PPI therapy.Farmakoepidemiologiske analyser er nødvendige som bakgrunn for å evaluere legemiddelbruk og gjøre kostnads-effektivitets prioriteringer. Databaser med informasjon om salg og forskrivning av legemidler er nyttige redskaper for slike analyser. I denne oppgaven presenteres en analyse av salgs- og forskrivningsdata for protonpumpehemmere, en legemiddelgruppe som brukes ved syrerelaterte gasterointestinale sykdommer. Forbruket av protonpumpehemmere i Norge har siden 1996 økt med 10 % per år, med esomeprazol som vanligste legemiddel. Et økende antall personer bruker disse legemidlene. Utgiftene for det offentlige trygdesystemet er omfattende, mer enn 450 millioner NOK i 2006. Verifisert spiserørbetennelse er den dominerende årsak til forskrivning angitt på reseptene. Det er indikasjoner på en for høy forskrivning av protonpumpehemmere. Forskrivningen i Norge er forskjellig fra Danmark og Sverige, både med hensyn på valg av legemiddel og forbruksnivå. Prevalens for bruk av protonpumpehemmere øker med alder og når et maksimum på nær 12 % av befolkningen i aldersgruppene 70-79 og 80-89 år. En betydelig andel bruker legemidlene over lengre tid (> 2 år). Dette er grupper som bruker mange legemidler samtidig (polyfarmasi). Selv om protonpumpehemmerne har vært på markedet i mange år, diskuteres fortsatt negative følger av langtidsbruk og det er behov for å studere bruken nærmere. Oppmerksomheten bør rettes mot rasjonell bruk av disse legemidlene, ikke bare hvordan utgiftene til dem skal kunne reduseres.
ISBN 978-91-85721-14-6
3
Hansen, Peder. "Approximating the Binomial Distribution by the Normal Distribution – Error and Accuracy". Thesis, Uppsala universitet, Matematisk statistik, 2011. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-155336.
Pełny tekst źródła
4
Hardy, James C. (James Clifford). "A Monte Carlo Study of the Robustness and Power Associated with Selected Tests of Variance Equality when Distributions are Non-Normal and Dissimilar in Form". Thesis, University of North Texas, 1990. https://digital.library.unt.edu/ark:/67531/metadc332130/.
Pełny tekst źródłaStreszczenie:
When selecting a method for testing variance equality, a researcher should select a method which is robust to distribution non-normality and dissimilarity. The method should also possess sufficient power to ascertain departures from the equal variance hypothesis. This Monte Carlo study examined the robustness and power of five tests of variance equality under specific conditions. The tests examined included one procedure proposed by O'Brien (1978), two by O'Brien (1979), and two by Conover, Johnson, and Johnson (1981). Specific conditions included assorted combinations of the following factors: k=2 and k=3 groups, normal and non-normal distributional forms, similar and dissimilar distributional forms, and equal and unequal sample sizes. Under the k=2 group condition, a total of 180 combinations were examined. A total of 54 combinations were examined under the k=3 group condition. The Type I error rates and statistical power estimates were based upon 1000 replications in each combination examined. Results of this study suggest that when sample sizes are relatively large, all five procedures are robust to distribution non-normality and dissimilarity, as well as being sufficiently powerful.
5
Melbourne, Davayne A. "A New method for Testing Normality based upon a Characterization of the Normal Distribution". FIU Digital Commons, 2014. http://digitalcommons.fiu.edu/etd/1248.
Pełny tekst źródłaStreszczenie:
The purposes of the thesis were to review some of the existing methods for testing normality and to investigate the use of generated data combined with observed to test for normality. The approach to testing for normality is in contrast to the existing methods which are derived from observed data only. The test of normality proposed follows a characterization theorem by Bernstein (1941) and uses a test statistic D*, which is the average of the Hoeffding’s D-Statistic between linear combinations of the observed and generated data to test for normality.
Overall, the proposed method showed considerable potential and achieved adequate power for many of the alternative distributions investigated. The simulation results revealed that the power of the test was comparable to some of the most commonly used methods of testing for normality. The test is performed with the use of a computer-based statistical package and in general takes a longer time to run than some of the existing methods of testing for normality.
6
Karlsson, Faronius Håkan. "On the Implementation of Computer Intensive Methods in Linear Normal Models". Thesis, Uppsala universitet, Tillämpad matematik och statistik, 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-447013.
Pełny tekst źródła
7
Liesch, Rahel. "Statistical Genetics for the Budset in Norway Spruce". Thesis, Uppsala University, Department of Mathematics, 2005. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-121386.
Pełny tekst źródła
8
EBRAHIMI, ROUHOLLAH. "EXTREME VALUE STATISTICS OF RANDOM NORMAL MATRICES". PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIRO, 2017. http://www.maxwell.vrac.puc-rio.br/Busca_etds.php?strSecao=resultado&nrSeq=36996@1.
Pełny tekst źródłaStreszczenie:
PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIROCOORDENAÇÃO DE APERFEIÇOAMENTO DO PESSOAL DE ENSINO SUPERIOR
CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO
PROGRAMA DE SUPORTE À PÓS-GRADUAÇÃO DE INSTS. DE ENSINO
Com diversas aplicações em matemática, física e finanças, Teoria das Matrizes Aleatórias (RMT) recentemente atraiu muita atenção. Enquanto o RMT Hermitiano é de especial importância na física por causa da Hermenticidade de operadores associados a observáveis em mecânica quântica, O RMT não-Hermitiano também atraiu uma atenção considerável, em particular porque eles podem ser usados como modelos para sistemas físicos dissipativos ou abertos. No entanto, devido à ausência de uma simetria simplificada, o estudo de matrizes aleatórias não-Hermitianas é, em geral, uma tarefa difícil. Um subconjunto especial de matrizes aleat órias não-Hermitianas, as chamadas matrizes aleatórias normais, são modelos interessantes a serem considerados, uma vez que oferecem mais simetria, tornando-as mais acessíveis às investigções analíticas. Por definição, uma matriz normal M é uma matriz quadrada que troca com seu adjunto Hermitiano. Nesta tese, amplicamos a derivação de estatísticas de valores extremos (EVS) de matrizes aleatórias Hermitianas, com base na abordagem de polinômios ortogonais, em matrizes aleatórias normais e em gases Coulomb 2D em geral. A força desta abordagem a sua compreensão física e intuitiva. Em primeiro lugar, essa abordagem fornece uma derivação alternativa de resultados na literatura. Precisamente falando, mostramos a convergência do autovalor redimensionado com o maior módulo de um conjunto de Ginibre para uma distribuição de Gumbel, bem como a universalidade para um potencial arbitrário radialmente simtérico que atenda certas condições. Em segundo lugar, mostra-se que esta abordagem pode ser generalizada para obter a convergência do autovalor com menor módulo e sua universalidade no limite interno finito do suporte do autovalor. Um aspecto interessante deste trabalho é o fato de que podemos usar técnicas padrão de matrizes aleatórias Hermitianas para obter o EVS de matrizes aleatórias não Hermitianas.
With diverse applications in mathematics, physics, and finance, Random Matrix Theory (RMT) has recently attracted a great deal of attention. While Hermitian RMT is of special importance in physics because of the Hermiticity of operators associated with observables in quantum mechanics, non-Hermitian RMT has also attracted a considerable attention, in particular because they can be used as models for dissipative or open physical systems. However, due to the absence of a simplifying symmetry, the study of non-Hermitian random matrices is, in general, a diffcult task. A special subset of non-Hermitian random matrices, the so-called random normal matrices, are interesting models to consider, since they offer more symmetry, thus making them more amenable to analytical investigations. By definition, a normal matrix M is a square matrix which commutes with its Hermitian adjoint, i.e., (M, M (1)). In this thesis, we present a novel derivation of extreme value statistics (EVS) of Hermitian random matrices, namely the approach of orthogonal polynomials, to normal random matrices and 2D Coulomb gases in general. The strength of this approach is its physical and intuitive understanding. Firstly, this approach provides an alternative derivation of results in the literature. Precisely speaking, we show convergence of the rescaled eigenvalue with largest modulus of a Ginibre ensemble to a Gumbel distribution, as well as universality for an arbitrary radially symmetric potential which meets certain conditions. Secondly, it is shown that this approach can be generalised to obtain convergence of the eigenvalue with smallest modulus and its universality at the finite inner edge of the eigenvalue support. One interesting aspect of this work is the fact that we can use standard techniques from Hermitian random matrices to obtain the EVS of non-Hermitian random matrices.
9
Hedell, Ronny. "Rarities of genotype profiles in a normal Swedish population". Thesis, Linköpings universitet, Matematiska institutionen, 2010. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-59708.
Pełny tekst źródłaStreszczenie:
Investigation of stains from crime scenes are commonly used in the search for criminals. At The National Laboratory of Forensic Science, where these stains are examined, a number of questions of theoretical and practical interest regarding the databases of DNA profiles and the strength of DNA evidence against a suspect in a trial are not fully investigated. The first part of this thesis deals with how a sample of DNA profiles from a population is used in the process of estimating the strength of DNA evidence in a trial, taking population genetic factors into account. We then consider how to combine hypotheses regarding the relationship between a suspect and other possible donors of the stain from the crime scene by two applications of Bayes’ theorem. After that we assess the DNA profiles that minimize the strength of DNA evidence against a suspect, and investigate how the strength is affected by sampling error using the bootstrap method and a Bayesian method. In the last part of the thesis we examine discrepancies between different databases of DNA profiles by both descriptive and inferential statistics, including likelihood ratio tests and Bayes factor tests. Little evidence of major differences is found.
10
Kelly, Joseph. "Advances in the Normal-Normal Hierarchical Model". Thesis, Harvard University, 2014. http://dissertations.umi.com/gsas.harvard:11498.
Pełny tekst źródła
11
Pillala, Lavanya. "Use Of Web-Based Lessons Of Statistical Concepts With Graphics And Animation To Enhance The Effectiveness Of Learning". Wright State University / OhioLINK, 2010. http://rave.ohiolink.edu/etdc/view?acc_num=wright1268779325.
Pełny tekst źródła
12
Zhao, Yanchun. "Comparison of Proposed K Sample Tests with Dietz's Test for Nondecreasing Ordered Alternatives for Bivariate Normal Data". Thesis, North Dakota State University, 2011. https://hdl.handle.net/10365/28836.
Pełny tekst źródłaStreszczenie:
There are many situations in which researchers want to consider a set of response variables simultaneously rather than just one response variable. For instance, a possible example is when a researcher wishes to determine the effects of an exercise and diet program on both the cholesterol levels and the weights of obese subjects. Dietz (1989) proposed two multivariate generalizations of the Jonckheere test for ordered alternatives. In this study, we propose k-sample tests for nondecreasing ordered alternatives for bivariate normal data and compare their powers with Dietz's sum statistic. The proposed k-sample tests are based on transformations of bivariate data to univariate data. The transformations considered are the sum, maximum and minimum functions. The ideas for these transformations come from the Leconte, Moreau, and Lellouch (1994). After the underlying bivariate normal data are reduced to univariate data, the Jonckheere-Terpstra (JT) test (Terpstra, 1952 and Jonckheere, 1954) and the Modified Jonckheere-Terpstra (MJT) test (Tryon and Hettmansperger, 1973) are applied to the univariate data. A simulation study is conducted to compare the proposed tests with Dietz's test for k bivariate normal populations (k=3, 4, 5). A variety of sample sizes and various location shifts are considered in this study. Two different correlations are used for the bivariate normal distributions. The simulation results show that generally the Dietz test performs the best for the situations considered with the underlying bivariate normal distribution. The estimated powers of MJT sum and JT sum are often close with the MJT sum generally having a little higher power. The sum transformation was the best of the three transformations to use for bivariate normal data.
13
Opperman, Logan J. "Sequential Inference and Nonparametric Goodness-of-Fit Tests for Certain Types of Skewed Distributions". Bowling Green State University / OhioLINK, 2019. http://rave.ohiolink.edu/etdc/view?acc_num=bgsu1560856288455652.
Pełny tekst źródła
14
Linder, Richard Scott. "Impact of censoring on sample variances and regression coefficient in a bivariate normal model /". The Ohio State University, 1998. http://rave.ohiolink.edu/etdc/view?acc_num=osu148795190795651.
Pełny tekst źródła
15
Chavarria, Pablo C. "Reduction of Confidence Interval Length for Small-Normal Data Sets Utilizing Bootstrap and Conformal Prediction Methods". Thesis, California State University, Long Beach, 2018. http://pqdtopen.proquest.com/#viewpdf?dispub=10840988.
Pełny tekst źródłaStreszczenie:
It is of common practice to evoke a t-confidence interval for estimating the mean of a small data set with an assumed Normal distribution. These t-intervals are known to be wide to account for the lack of information. This thesis will focus on exploring ways to reduce the length of the interval, while preserving the level of confidence. Simulated small normal data sets will be used to analyze a combination of Bootstrapping and Conformal Prediction methods, while investigating measures of spread, such as standard deviation, kurtosis, excess CS kurtosis, skewness, etc. to create a criterion for when this combination of methodologies will greatly reduce the interval length. The goal is to be able to use the insight simulated data have to offer in order to apply to real world data. If time permits, a further look into the theory behind the results will be explored.
16
Gottfridsson, Anneli. "Likelihood ratio tests of separable or double separable covariance structure, and the empirical null distribution". Thesis, Linköpings universitet, Matematiska institutionen, 2011. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-69738.
Pełny tekst źródłaStreszczenie:
The focus in this thesis is on the calculations of an empirical null distributionfor likelihood ratio tests testing either separable or double separable covariancematrix structures versus an unstructured covariance matrix. These calculationshave been performed for various dimensions and sample sizes, and are comparedwith the asymptotic χ2-distribution that is commonly used as an approximative distribution. Tests of separable structures are of particular interest in cases when data iscollected such that more than one relation between the components of the observationis suspected. For instance, if there are both a spatial and a temporalaspect, a hypothesis of two covariance matrices, one for each aspect, is reasonable.
17
Wang, Sheng. "Regularized skewness parameter estimation for multivariate skew normal and skew t distributions". Diss., University of Iowa, 2019. https://ir.uiowa.edu/etd/6875.
Pełny tekst źródłaStreszczenie:
The skewed normal (SN) distribution introduced by Azzalini has opened a new era for analyzing skewed data. The idea behind it is that it incorporates a new parameter regulating shape and skewness on the symmetric Gaussian distribution. This idea was soon extended to other symmetric distributions such as the Student's t distribution, resulting in the invention of the skew t (ST) distribution.
The multivariate versions of the two distributions, i.e. the multivariate skew normal (MSN) and multivariate skew t (MST) distributions, have received considerable attention because of their ability to t skewed data, together with some other properties such as mathematical tractability. While many researchers focus on tting the MSN and MST dis- tributions to data, in this thesis we address another important aspect of statistical modeling using those two distributions, i.e. skewness selection and estimation. Skewness selection, as we discuss it here, means identifying which components of the skewness parameter in the MSN and MST distributions are zero.
In this thesis, we begin by reviewing some important properties of the two distributions and then we describe the obstacles that block us from doing skewness selection in the direct parameterizations of the two distributions. Then, to circumvent those obstacles, we intro- duce a new parameterization to use for skewness selection. The nice properties of this new parameterization are also summarized.
After introduction of the new parameterization, we discuss our proposed methods to reach the goal of skewness selection. Particularly, we consider adding appropriate penalties to the loss functions of the MSN and MST distributions, represented in the new parameterization of the two distributions. Technical details such as initial value selection and tuning parameter selection are also discussed. Asymptotic consistency and oracle property of some of our methods are constructed.
In the later part of the thesis, we include results from some simulation studies in order to assess the performance of our proposed methods. Also, we apply our methods to three data sets. Lastly, some drawbacks and potential future work are discussed.
18
Tazhibi, Mehdi. "Estimation of the parameters in the truncated normal distribution when the truncation point is known". Thesis, University of Southampton, 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.242267.
Pełny tekst źródła
19
Tran, Dinh Hai 1966. "Atmospheric model and data analysis in terms of empirical normal modes". Thesis, McGill University, 1998. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=35504.
Pełny tekst źródłaStreszczenie:
The Empirical Orthogonal Function (EOF) analysis technique has proven to be one of the most powerful methods to analyze data in meteorology and many other fields. However, this method is statistical only and has no physical basis. Brunet (1994) has introduced Held's (1985) concept of conservation of wave activity and orthogonal functions into the EOF analysis and called it the "Empirical Normal Mode" (ENM) analysis technique. This new method uses both statistical concepts from the classical EOF analysis method and a dynamical constraint from the generalized Eliassen-Palm theorem to ensure that the functions that we obtained are orthogonal to each other and are the solutions of linearized dynamical equations.In this thesis, we use the ENM analysis to analyze data from both a (2D) shallow water model integration and from 3-D atmospheric observations, with an emphasis on stratospheric sudden warming events.
For the shallow water model case, the results of the ENM analysis are evaluated by testing against the theoretical (numerical) normal mode solutions provided by Longuet-Higgins (1968). It is shown that the ENM analysis can recover the spatial structures and the frequencies of the normal modes with a great degree of accuracy if the temporal record is sufficiently long. The average errors in the periods for 2000 and 100 day time series are found to be 1% and 4.6%, respectively. From the eigenvalues (percentage of the total variance) and sharp frequency peaks associated with normal modes, the ENM analysis shows that the model generates only a few modes with monochromatic frequencies. The method can be used to test a new or modified shallow water model integration or to study other Hough modes generated by different kinds of forcings.
Having shown the value of the ENM technique in a barotropic context, we advance further by performing an ENM analysis on an 11 year atmospheric data set. In this study, we focus on stratospheric warming events. The winter (DJF) data set is partitioned into warming and non-warming periods in order to characterize the flow differences between the regimes. The stratospheric quasi-potential vorticity or wave activity structure in the warming period is found to be much stronger, as expected, than in the non-warming periods. The ENM analysis clearly shows the tropospheric difference between the two periods, e.g., a higher wave activity in the main tropospheric structure as well as in the tropospheric polar regions in the warming periods. The analysis also reveals that there is a higher level of stratospheric wave activity during the warming periods in the second normal mode of zonal wave number 1 but the tropospheric structures of the quasi-potential vorticity are the same as during non-warming periods. This suggests that there is/are (a) mechanism(s) associated with the stratospheric warming other than the upward wave propagation. All the common features of the stratospheric warming event are captured by the first two normal modes of zonal wave numbers 1 and 2, such as wave-mean flow interaction leading to the deceleration of the zonal mean wind, the polar vortex being displaced by the northward movement of the Aleutian High, as well as wave amplitude enhancement/reduction during the growing/decaying stages.
20
Li, Xue. "Statistical Inference for the Common Mean of Two Independent Log-Normal Distributions and Some Applications in Reliability". Fogler Library, University of Maine, 2004. http://www.library.umaine.edu/theses/pdf/LiX2004a.pdf.
Pełny tekst źródła
21
Ngunkeng, Grace. "Statistical Analysis of Skew Normal Distribution and its Applications". Bowling Green State University / OhioLINK, 2013. http://rave.ohiolink.edu/etdc/view?acc_num=bgsu1370958073.
Pełny tekst źródła
22
Li, Xiaosong. "Testing on the Common Mean of Normal Distributions Using Bayesian Method". Case Western Reserve University School of Graduate Studies / OhioLINK, 2011. http://rave.ohiolink.edu/etdc/view?acc_num=case1301420382.
Pełny tekst źródła
23
Luo, Hao. "Some Aspects on Confirmatory Factor Analysis of Ordinal Variables and Generating Non-normal Data". Doctoral thesis, Uppsala universitet, Statistiska institutionen, 2011. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-149423.
Pełny tekst źródłaStreszczenie:
This thesis, which consists of five papers, is concerned with various aspects of confirmatory factor analysis (CFA) of ordinal variables and the generation of non-normal data. The first paper studies the performances of different estimation methods used in CFA when ordinal data are encountered. To take ordinality into account the four estimation methods, i.e., maximum likelihood (ML), unweighted least squares, diagonally weighted least squares, and weighted least squares (WLS), are used in combination with polychoric correlations. The effect of model sizes and number of categories on the parameter estimates, their standard errors, and the common chi-square measure of fit when the models are both correct and misspecified are examined. The second paper focuses on the appropriate estimator of the polychoric correlation when fitting a CFA model. A non-parametric polychoric correlation coefficient based on the discrete version of Spearman's rank correlation is proposed to contend with the situation of non-normal underlying distributions. The simulation study shows the benefits of using the non-parametric polychoric correlation under conditions of non-normality. The third paper raises the issue of simultaneous factor analysis. We study the effect of pooling multi-group data on the estimation of factor loadings. Given the same factor loadings but different factor means and correlations, we investigate how much information is lost by pooling the groups together and only estimating the combined data set using the WLS method. The parameter estimates and their standard errors are compared with results obtained by multi-group analysis using ML. The fourth paper uses a Monte Carlo simulation to assess the reliability of the Fleishman's power method under various conditions of skewness, kurtosis, and sample size. Based on the generated non-normal samples, the power of D'Agostino's (1986) normality test is studied. The fifth paper extends the evaluation of algorithms to the generation of multivariate non-normal data. Apart from the requirement of generating reliable skewness and kurtosis, the generated data also need to possess the desired correlation matrices. Four algorithms are investigated in terms of simplicity, generality, and reliability of the technique.
24
Wu, Jing. "Statistical approaches to gender classification in the surface normal domain". Thesis, University of York, 2009. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.516723.
Pełny tekst źródła
25
Gardini, Aldo <1992>. "Bayesian inference for quantiles and conditional means in log-normal models". Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2020. http://amsdottorato.unibo.it/9349/1/Tesi_upload.pdf.
Pełny tekst źródłaStreszczenie:
The main topic of the thesis is the proper execution of a Bayesian inference if log-normality is assumed for data. In fact, it is known that a particular care is required in this context, since the most common prior distributions for the variance in log scale produce posteriors for the log-normal mean which do not have finite moments. Hence, classical summary measures of the posterior such as expectation and variance cannot be computed for these distributions.
The thesis is aimed at proposing solutions to carry out Bayesian inference inside a mathematically coherent framework, focusing on the estimation of two quantities: log-normal quantiles (first part of the thesis) and conditioned expectations under a general log-normal linear mixed model (second part of the thesis). Moreover, in the latter section, a further investigation on a unit-level small area models is presented, considering the problem of estimating the well-known log-transformed Battese, Harter and Fuller model in the hierarchical Bayes context.
Once the existence conditions for the moments of the target functionals posterior are proved, new strategies to specify prior distributions are suggested. Then, the frequentist properties of the deduced Bayes estimators and credible intervals are evaluated through accurate simulations studies: it resulted that the proposed methodologies improve the Bayesian estimates under naive prior settings and are satisfactorily competitive with the frequentist solutions available in the literature.
To conclude, applications of the developed inferential strategies are illustrated on real datasets.
The work is completed by the implementation of an R package named BayesLN which allows the users to easily carry out Bayesian inference for log-normal data.
26
Burrill, Gail. "The Role of Dynamic Interactive Technology in Teaching and Learning Statistics". Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2012. http://nbn-resolving.de/urn:nbn:de:bsz:14-qucosa-79544.
Pełny tekst źródłaStreszczenie:
Dynamic interactive technology brings new opportunities for helping students learn central statistical concepts. Research and classroom experience can be help identify concepts with which students struggle,
and an \"action-consequence\" pre-made technology document can engage students in exploring these concepts. With the right questions, students can begin to make connections among their background in
mathematics, foundational ideas that undergrid statistics and the relationship these ideas. The ultimate goal is to have students think deeply about simple and basic statistical ideas so they can see how they lead to reasoning and sense making about data and about making decisions about characteristics of a population from a sample.Technology has a critical role in teaching and learning statistics, enabling students to use real data in investigations, to model complex situations based on data, to visualize
relationships using different representations, to move beyond calculations to interpreting statistical processes such as confidence intervals and correlation, and to generate simulations to investigate a variety of problems including laying a foundation for inference. Thus, graphing calculators, spreadsheets, and interactive dynamic software can all be thought of as tools for statistical sense making in the service of developing understanding.
27
Roberts, Lucas R. "Variable Selection and Decision Trees: The DiVaS and ALoVaS Methods". Diss., Virginia Tech, 2014. http://hdl.handle.net/10919/70878.
Pełny tekst źródłaStreszczenie:
In this thesis we propose a novel modification to Bayesian decision tree methods. We provide a
historical survey of the statistics and computer science research in decision trees. Our approach
facilitates covariate selection explicitly in the model, something not present in previous research.
We define a transformation that allows us to use priors from linear models to facilitate covariate
selection in decision trees. Using this transform, we modify many common approaches to variable
selection in the linear model and bring these methods to bear on the problem of explicit covariate
selection in decision tree models. We also provide theoretical guidelines, including a theorem,
which gives necessary and sufficient conditions for consistency of decision trees in infinite dimensional
spaces. Our examples and case studies use both simulated and real data cases with moderate
to large numbers of covariates. The examples support the claim that our approach is to be preferred
in large dimensional datasets. Moreover, our approach shown here has, as a special case, the model
known as Bayesian CART.Ph. D.
28
Rajaram, Lakshminarayan. "Statistical models in environmental and life sciences". [Tampa, Fla] : University of South Florida, 2006. http://purl.fcla.edu/usf/dc/et/SFE0001561.
Pełny tekst źródła
29
Huang, Ching-ying Maghsoodloo Saeed. "Comparing the overlapping of two independent confidence intervals with a single confidence interval for two normal population parameters". Auburn, Ala, 2008. http://hdl.handle.net/10415/1480.
Pełny tekst źródła
30
Pavlika, Vasos. "A Discussion of different teaching strategies adopted during a Statistics tutorial". Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2012. http://nbn-resolving.de/urn:nbn:de:bsz:14-qucosa-88200.
Pełny tekst źródłaStreszczenie:
In this discusses four different approaches used during a statistics tutorial of a group of first year undergraduates studying computer science related degrees at the University of Westminster UK. The four approaches were each implemented in an attempt to keep the students interested in the statistics topics delivered. It was found that “Chalk and Talk” (i.e. board work) was not the best form of imparting knowledge to the students of the group as determined by student analysing feedback forms and generally observing student behaviour and listening to student comments over a number of years delivering statistics topics. The duration of each tutorial was two hours.
The teaching strategies adopted were:
a) A class quiz.
b) Group explanation of material to members of the individual’s group.
c) Group explanation of material to members of the entire class.
d) Students teaching at the front of the class.
Each of the methods will now be discussed with the relative merits and defects included for a comparison. It was found that each method worked better at the end of each module when the students were more familiar with the topics introduced on the module.
31
Mutz, Sebastian [Verfasser], Heiko [Gutachter] Paeth i Stefan [Gutachter] Winkler. "Dynamic Statistical Modelling of Climate-Related Mass Balance Changes in Norway / Sebastian Mutz. Gutachter: Heiko Paeth ; Stefan Winkler". Würzburg : Universität Würzburg, 2015. http://d-nb.info/1111783829/34.
Pełny tekst źródła
32
Tchouta, Romual Eloge. "Estimating the Difference of Percentiles from Two Independent Populations". Digital Commons @ East Tennessee State University, 2008. https://dc.etsu.edu/etd/1981.
Pełny tekst źródłaStreszczenie:
We first consider confidence intervals for a normal percentile, an exponential percentile and a uniform percentile. Then we develop confidence intervals for a difference of percentiles from two independent normal populations, two independent exponential populations and two independent uniform populations. In our study, we mainly focus on the maximum likelihood to develop our confidence intervals. The efficiency of this method is examined via coverage rates obtained in a simulation study done with the statistical software R.
33
Kelbick, Nicole DePriest. "Detecting underlying emotional sensitivity in bereaved children via a multivariate normal mixture distribution". Columbus, Ohio : Ohio State University, 2003. http://rave.ohiolink.edu/etdc/view?acc%5fnum=osu1064331329.
Pełny tekst źródłaStreszczenie:
Thesis (Ph. D.)--Ohio State University, 2003.Title from first page of PDF file. Document formatted into pages; contains xiv, 122 p.; also contains graphics. Includes abstract and vita. Advisor: Joseph, Dept. of Statistics. Includes bibliographical references (p. 119-122).
34
Wu, Yun. "A simulation study of the robustness of Hotelling’s T2 test for the mean of a multivariate distribution when sampling from a multivariate skew-normal distribution". Kansas State University, 2009. http://hdl.handle.net/2097/1939.
Pełny tekst źródłaStreszczenie:
Master of ScienceDepartment of Statistics
Paul I. Nelson
Hotelling’s T2 test is the standard tool for inference about the mean of a multivariate normal population. However, this test may perform poorly when used on samples from multivariate distributions with highly skewed marginal distributions. The goal of our study was to investigate the type I error rate and power properties of Hotelling’s one sample test when sampling from a class of multivariate skew-normal (SN) distributions, which includes the multivariate normal distribution and, in addition to location and scale parameters, has a shape parameter to regulate skewness. Simulation results of tests carried out at nominal type I error rate 0.05 obtained from various levels of shape parameters, sample sizes, number of variables and fixed correlation matrix showed that Hotelling’s one sample test provides adequate control of type I error rates over the entire range of conditions studied. The test also produces suitable power levels for detecting departures from hypothesized values of a multivariate mean vector when data result from a random sample from a multivariate SN. The shape parameter of the SN family appears not to have much of an effect on the robustness of Hotelling’s test. However, surprisingly, it does have a positive impact on power.
35
Bear, John Stanley, i John Stanley Bear. "A Logistic Normal Mixture Model for Compositions with Essential Zeros". Diss., The University of Arizona, 2016. http://hdl.handle.net/10150/621758.
Pełny tekst źródłaStreszczenie:
Compositions are vectors of nonnegative numbers that sum to a constant, usually one or 100%. They arise in a wide array of fields: geological sampling, budgets,fat/protein/carbohydrate in foods, percentage of the vote acquired by each political party, and more. The usual candidate distributions for modeling compositions -- the Dirichlet and the logistic normal distribution -- have density zero if any component is zero. While statistical methods have been developed for "rounded" zeros, zeros stemming from values below a detection level, and zeros arising from count data, there remain problems with essential zeros, i.e. cases in continuous compositions where a component is truly absent. We develop a model for compositions with essential zeros based on an approach by Aitchison and Kay (2003). It uses a mixture of additive logistic normal distributions of different dimension, related by common parameters. With the requirement of an additional constraint, we develop a likelihood and methods estimating parameters for location and dispersion. We also develop a permutation test for a two-group comparison, and demonstrate the model and test using data from a diabetes study. These results provide the first use of the additive logistic normal distribution formodeling and testing compositional data in the presence of essential zeros.
36
Wang, Xing. "Inferences about Parameters of Trivariate Normal Distribution with Missing Data". FIU Digital Commons, 2013. http://digitalcommons.fiu.edu/etd/933.
Pełny tekst źródłaStreszczenie:
Multivariate normal distribution is commonly encountered in any field, a frequent issue is the missing values in practice. The purpose of this research was to estimate the parameters in three-dimensional covariance permutation-symmetric normal distribution with complete data and all possible patterns of incomplete data. In this study, MLE with missing data were derived, and the properties of the MLE as well as the sampling distributions were obtained. A Monte Carlo simulation study was used to evaluate the performance of the considered estimators for both cases when ρ was known and unknown. All results indicated that, compared to estimators in the case of omitting observations with missing data, the estimators derived in this article led to better performance. Furthermore, when ρ was unknown, using the estimate of ρ would lead to the same conclusion.
37
Hattaway, James T. "Parameter Estimation and Hypothesis Testing for the Truncated Normal Distribution with Applications to Introductory Statistics Grades". Diss., CLICK HERE for online access, 2010. http://contentdm.lib.byu.edu/ETD/image/etd3412.pdf.
Pełny tekst źródła
38
Zhan, Tingting. "The Generalized Linear Mixed Model for Finite Normal Mixtures with Application to Tendon Fibrilogenesis Data". Diss., Temple University Libraries, 2012. http://cdm16002.contentdm.oclc.org/cdm/ref/collection/p245801coll10/id/171613.
Pełny tekst źródłaStreszczenie:
StatisticsPh.D.
We propose the generalized linear mixed model for finite normal mixtures (GLMFM), as well as the estimation procedures for the GLMFM model, which are widely applicable to the hierarchical dataset with small number of individual units and multi-modal distributions at the lowest level of clustering. The modeling task is two-fold: (a). to model the lowest level cluster as a finite mixtures of the normal distribution; and (b). to model the properly transformed mixture proportions, means and standard deviations of the lowest-level cluster as a linear hierarchical structure. We propose the robust generalized weighted likelihood estimators and the new cubic-inverse weight for the estimation of the finite mixture model (Zhan et al., 2011). We propose two robust methods for estimating the GLMFM model, which accommodate the contaminations on all clustering levels, the standard-two-stage approach (Chervoneva et al., 2011, co-authored) and a robust joint estimation. Our research was motivated by the data obtained from the tendon fibril experiment reported in Zhang et al. (2006). Our statistical methodology is quite general and has potential application in a variety of relatively complex statistical modeling situations.
Temple University--Theses
39
NAI, RUSCONE MARTA. "Modelli gerarchici: aspetti metodologici e ambiti di applicazione". Doctoral thesis, Università degli Studi di Milano-Bicocca, 2011. http://hdl.handle.net/10281/25272.
Pełny tekst źródłaStreszczenie:
Sempre più spesso e in vari ambiti disciplinari (come ad esempio nelle ricerche sociologiche, economiche, demografiche, epidemiologiche) si analizzano fenomeni con una struttura informativa gerarchica, in cui i dati si riferiscono a più livelli di osservazione/appartenenza: individuale, familiare, territoriale, sociale e così via. In particolare, lo studio delle relazioni tra l'individuo e il contesto che lo circonda può essere ricondotto all'analisi di fenomeni a struttura gerarchica. I modelli che si sono manifestati più idonei al trattamento di dati con struttura complessa sono i cosiddetti Multilevel Model. Questa classe è caratterizzata dalle seguenti dimensioni di analisi: una dimensione micro, relativa all'individuo, e una dimensione macro, riferita al contesto in cui l'individuo vive, formalizzando l'interazione individuo/ambiente attraverso lo studio dell'effetto di opportune variabili, cosiddette macro, sulle scelte e sui comportamenti individuali. L'effetto delle variabili a livello macro su quelle a livello micro può essere definito moderante, poichè l'influenza che esso rappresenta condiziona la relazione di tipo causale tra le variabili di risposta e quelle esplicative (esse sono componenti essenziali di qualsiasi analisi di regressione). Tra i principali aspetti di questa classe di modelli è possibile individuare l'elevata complessità, in presenza di un numero elevato di livelli o di variabili esplicative. La metodologia dei modelli multilivello consente l'analisi di dati organizzati in una struttura di tipo gerarchico, ossia di dati raggruppati.
Nella teoria "classica" si introduce poi, ai fini inferenziali, l'ipotesi distributiva normale per le componenti d'errore. Tuttavia in alcuni casi tale assunzione può rilevarsi troppo restrittiva. Uno degli obiettivi di questa tesi è stato di proporre, quale alternativa alla normale, la distribuzione Skew-Normal (SN) (Azzalini, Dalla Valle, 1996), che include come caso speciale la distribuzione normale e riesce a modellare i più svariati andamenti, adattandosi in modo più appropriato alle situazioni presenti in natura. La SN permette di migliorare l'approccio all'analisi potendo "manipolare", anche se non direttamente, la simmetria della distribuzione. Si metteranno in luce l'utilità di impiego della SN nell'ambito dell'analisi multilivello e si discuteranno i principali problemi legati alla stima dei parametri.
40
Liu, Yingying. "Bayesian hierarchical normal intrinsic conditional autoregressive model for stream networks". Diss., University of Iowa, 2018. https://ir.uiowa.edu/etd/6606.
Pełny tekst źródłaStreszczenie:
Water quality and river/stream ecosystems are important for all living creatures. To protect human health, aquatic life and the surrounding ecosystem, a considerable amount of time and money has been spent on sampling and monitoring streams and rivers. Water quality monitoring and analysis can help researchers predict and learn from natural processes in the environment and determine human impacts on an ecosystem. Measurements such as temperature, pH, nitrogen concentration, algae and fish count collected along the network are all important factors in water quality analysis. The main purposes of the statistical analysis in this thesis are (1) to assess the relationship between the variable measured in the water (response variable) and other variables that describe either the locations on/along the stream network or certain characteristics at each location (explanatory variable), and (2) to assess the degree of similarity between the response variable values measured at different locations of the stream, i.e. spatial dependence structure. It is commonly accepted that measurements taken at two locations close to each other should have more similarity than locations far away. However, this is not always true for observations from stream networks. Observations from two sites that do not share water flow could be independent of each other even if they are very close in terms of stream distance, especially those observations taken on objects that move passively with the water flow. To model stream network data correctly, it is important to quantify the strength of association between observations from sites that do not share water.
41
Gordon, Carol J. (Carol Jean). "The Robustness of O'Brien's r Transformation to Non-Normality". Thesis, North Texas State University, 1985. https://digital.library.unt.edu/ark:/67531/metadc332002/.
Pełny tekst źródłaStreszczenie:
A Monte Carlo simulation technique was employed in this study to determine if the r transformation, a test of homogeneity of variance, affords adequate protection against Type I error over a range of equal sample sizes and number of groups when samples are obtained from normal and non-normal distributions. Additionally, this study sought to determine if the r transformation is more robust than Bartlett's chi-square to deviations from normality. Four populations were generated representing normal, uniform, symmetric leptokurtic, and skewed leptokurtic distributions. For each sample size (6, 12, 24, 48), number of groups (3, 4, 5, 7), and population distribution condition, the r transformation and Bartlett's chi-square were calculated. This procedure was replicated 1,000 times; the actual significance level was determined and compared to the nominal significance level of .05. On the basis of the analysis of the generated data, the following conclusions are drawn. First, the r transformation is generally robust to violations of normality when the size of the samples tested is twelve or larger. Second, in the instances where a significant difference occurred between the actual and nominal significance levels, the r transformation produced (a) conservative Type I error rates if the kurtosis of the parent population were 1.414 or less and (b) an inflated Type I error rate when the index of kurtosis was three. Third, the r transformation should not be used if sample size is smaller than twelve. Fourth, the r transformation is more robust in all instances to non-normality, but the Bartlett test is superior in controlling Type I error when samples are from a population with a normal distribution. In light of these conclusions, the r transformation may be used as a general utility test of homogeneity of variances when either the distribution of the parent population is unknown or is known to have a non-normal distribution, and the size of the equal samples is at least twelve.
42
Reinhammar, Ragna. "Estimation of Regression Coefficients under a Truncated Covariate with Missing Values". Thesis, Uppsala universitet, Statistiska institutionen, 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-385672.
Pełny tekst źródłaStreszczenie:
By means of a Monte Carlo study, this paper investigates the relative performance of Listwise Deletion, the EM-algorithm and the default algorithm in the MICE-package for R (PMM) in estimating regression coefficients under a left truncated covariate with missing values. The intention is to investigate whether the three frequently used missing data techniques are robust against left truncation when missing values are MCAR or MAR. The results suggest that no technique is superior overall in all combinations of factors studied. The EM-algorithm is unaffected by left truncation under MCAR but negatively affected by strong left truncation under MAR. Compared to the default MICE-algorithm, the performance of EM is more stable across distributions and combinations of sample size and missing rate. The default MICE-algorithm is improved by left truncation but is sensitive to missingness pattern and missing rate. Compared to Listwise Deletion, the EM-algorithm is less robust against left truncation when missing values are MAR. However, the decline in performance of the EM-algorithm is not large enough for the algorithm to be completely outperformed by Listwise Deletion, especially not when the missing rate is moderate. Listwise Deletion might be robust against left truncation but is inefficient.
43
Uddin, Mohammad Moin. "ROBUST STATISTICAL METHODS FOR NON-NORMAL QUALITY ASSURANCE DATA ANALYSIS IN TRANSPORTATION PROJECTS". UKnowledge, 2011. http://uknowledge.uky.edu/gradschool_diss/153.
Pełny tekst źródłaStreszczenie:
The American Association of Highway and Transportation Officials (AASHTO) and Federal Highway Administration (FHWA) require the use of the statistically based quality assurance (QA) specifications for construction materials. As a result, many of the state highway agencies (SHAs) have implemented the use of a QA specification for highway construction. For these statistically based QA specifications, quality characteristics of most construction materials are assumed normally distributed, however, the normality assumption can be violated in several forms. Distribution of data can be skewed, kurtosis induced, or bimodal. If the process shows evidence of a significant departure from normality, then the quality measures calculated may be erroneous.
In this research study, an extended QA data analysis model is proposed which will significantly improve the Type I error and power of the F-test and t-test, and remove bias estimates of Percent within Limit (PWL) based pay factor calculation. For the F-test, three alternative tests are proposed when sampling distribution is non-normal. These are: 1) Levene’s test; 2) Brown and Forsythe’s test; and 3) O’Brien’s test. One alternative method is proposed for the t-test, which is the non-parametric Wilcoxon - Mann – Whitney Sign Rank test. For PWL based pay factor calculation when lot data suffer non-normality, three schemes were investigated, which are: 1) simple transformation methods, 2) The Clements method, and 3) Modified Box-Cox transformation using “Golden Section Search” method.
The Monte Carlo simulation study revealed that both Levene’s test and Brown and Forsythe’s test are robust alternative tests of variances when underlying sample population distribution is non-normal. Between the t-test and Wilcoxon test, the t-test was found significantly robust even when sample population distribution was severely non-normal. Among the data transformation for PWL based pay factor, the modified Box-Cox transformation using the golden section search method was found to be the most effective in minimizing or removing pay bias. Field QA data was analyzed to validate the model and a Microsoft® Excel macro based software is developed, which can adjust any pay consequences due to non-normality.
44
Somal, Harsimran S. "Heterogeneous computing for the Bayesian hierarchical normal intrinsic conditional autoregressive model with incomplete data". Diss., University of Iowa, 2016. https://ir.uiowa.edu/etd/2145.
Pełny tekst źródłaStreszczenie:
A popular model for spatial association is the conditional autoregressive (CAR) model, and generalizations exist in the literature that utilize intrinsic CAR (ICAR) models within spatial hierarchical models. One generalization is the class of Bayesian hierarchical normal ICAR models, abbreviated HNICAR. The Bayesian HNICAR model can be used to smooth areal or lattice data, estimate the directional strength of spatio-temporal associations, and make posterior predictions at each point in space or time. Furthermore, the Bayesian HNICAR model allows for sample-based posterior inference about model parameters and predictions. R package CARrampsOcl enables fast, independent sampling-based inference for a Bayesian HNICAR model when data are complete and the spatial precision matrix is expressible as a Kronecker sum of lower order matrices. This thesis presents an independent sampling algorithm to accommodate incomplete data and arbitrary precision structures, a parallelized implementation of the algorithm that can be executed on a wide range of hardware, including NVIDIA and AMD graphical processing units (GPUs) and multicore Intel CPUs, analysis of the effects of missingness on the posterior distribution of model parameters and predictive densities, and a survey of model comparison methods for CAR models. The merits of the model and algorithm are demonstrated through both simulation and analysis of an environmental data set.
45
Buturi, Leonardo Oliveira. "Aplicações básicas de estatística e da distribuição normal para o ensino médio". Universidade Estadual Paulista (UNESP), 2018. http://hdl.handle.net/11449/154534.
Pełny tekst źródłaStreszczenie:
Submitted by Leonardo Oliveira Buturi (leobuturi@gmail.com) on 2018-07-17T16:21:41Z
No. of bitstreams: 1
Dissertação Profmat - Leonardo Buturi - alterada.pdf: 1686348 bytes, checksum: 8e0b727cbf88ce5a17eec6b1ed68c981 (MD5)Approved for entry into archive by Elza Mitiko Sato null (elzasato@ibilce.unesp.br) on 2018-07-17T18:02:15Z (GMT) No. of bitstreams: 1 buturi_lo_me_sjrp.pdf: 1753373 bytes, checksum: 3ba02802ac4746292b08c145040278aa (MD5)
Made available in DSpace on 2018-07-17T18:02:16Z (GMT). No. of bitstreams: 1 buturi_lo_me_sjrp.pdf: 1753373 bytes, checksum: 3ba02802ac4746292b08c145040278aa (MD5) Previous issue date: 2018-06-15
Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
Tendo por finalidade apresentar um estudo conciso em alguns tópicos de Estatística, com ênfase em aplicações e na distribuição normal, este trabalho destina-se a alunos e professores do Ensino Médio, que tenham interesse em se aprofundar no estudo destes tópicos. Técnicas estatísticas, principalmente nos problemas que podem ser modelados utilizando-se a distribuição normal, são de interesse geral e muito utilizado nas áreas de biologia, ecologia, administração de empresas e negócios. Inicialmente, são apresentados vários conceitos de Estatística tais como gráficos, medidas de posição e dispersão, conceitos de probabilidade, a distribuição normal, intervalos de confiança para a posterior aplicação em dados envolvendo os preço de combustíveis e notas de alunos dos Ensinos Fundamental e Médio. Os tópicos são expostos de forma que seja acessível aos alunos do ensino médio e as aplicações são motivadoras para a utilização posterior das técnicas apresentadas
Having as purpose present a concise study on Statistics and Probability, with emphasis on applications and the normal distribution, this work is intended for students and High School teachers, who have an interest in deepening on these topics. Statistical techniques, mainly in problems that can be modeled using the normal distribution are of general interest and widely used in the areas of biology, ecology, business administration and business. Initially, are presented several concepts of Statistics such as position and dispersion measurements, probability concepts, normal distribution, simple confidence intervals and applications. Topics are exposed in a way that is accessible to high school students and the applications are motivating for the later use of the techniques presented.
5566715
46
Devamitta, Perera Muditha Virangika. "Robustness of normal theory inference when random effects are not normally distributed". Kansas State University, 2011. http://hdl.handle.net/2097/8786.
Pełny tekst źródłaStreszczenie:
Master of ScienceDepartment of Statistics
Paul I. Nelson
The variance of a response in a one-way random effects model can be expressed as the sum of the variability among and within treatment levels. Conventional methods of statistical analysis for these models are based on the assumption of normality of both sources of variation. Since this assumption is not always satisfied and can be difficult to check, it is important to explore the performance of normal based inference when normality does not hold. This report uses simulation to explore and assess the robustness of the F-test for the presence of an among treatment variance component and the normal theory confidence interval for the intra-class correlation coefficient under several non-normal distributions. It was found that the power function of the F-test is robust for moderately heavy-tailed random error distributions. But, for very heavy tailed random error distributions, power is relatively low, even for a large number of treatments. Coverage rates of the confidence interval for the intra-class correlation coefficient are far from nominal for very heavy tailed, non-normal random effect distributions.
47
Matos, Larissa Avila 1987. "Modelos lineares e não lineares de efeitos mistos para respostas censuradas usando as distribuições normal e t-Student multivariadas". [s.n.], 2012. http://repositorio.unicamp.br/jspui/handle/REPOSIP/306684.
Pełny tekst źródłaStreszczenie:
Orientador: Víctor Hugo Lachos DávilaDissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Matemática, Estatística e Computação Científica
Made available in DSpace on 2018-08-20T06:44:43Z (GMT). No. of bitstreams: 1 Matos_LarissaAvila_M.pdf: 2008810 bytes, checksum: 0aee0c4f4bbf58ba67490d26cdd300ba (MD5) Previous issue date: 2012
Resumo: Modelos mistos são geralmente usados para representar dados longitudinais ou de medidas repetidas. Uma complicação adicional surge quando a resposta é censurada, por exemplo, devido aos limites de quantificação do ensaio utilizado. Distribuições normais para os efeitos aleatórios e os erros residuais são geralmente assumidas, mas tais pressupostos fazem as inferências vulneráveis, 'a presença de outliers. Motivados por uma preocupação da sensibilidade para potenciais outliers ou dados com caudas mais pesadas do que a normal, pretendemos desenvolver nessa dissertação, inferência para modelos lineares e não lineares de efeito misto censurados (NLMEC / LMEC) com base na distribui ção t- Student multivariada, sendo uma alternativa flexível ao uso da distribuição normal correspondente. Propomos um algoritmo ECM para computar as estimativas de máxima verossimilhança para os NLMEC / LMEC. Este algoritmo utiliza expressões fechadas no passo-E, que se baseia em fórmulas para a média e a variância de uma distribui ção t-multivariada truncada. O algoritmo proposto é implementado, pacote tlmec do R. Também propomos aqui um algoritmo ECM exato para os modelos lineares e não lineares de efeito misto censurados, com base na distribuição normal multivariada, que nos permite desenvolver análise de influência local para modelos de efeito misto com base na esperança condicional da função log-verossilhança dos dados completos. Os procedimentos desenvolvidos são ilustrados com a análise longitudinal da carga viral do HIV, apresentada em dois estudos recentes sobre a AIDS
Abstract: Mixed models are commonly used to represent longitudinal or repeated measures data. An additional complication arises when the response is censored, for example, due to limits of quantification of the assay used. Normal distributions for random effects and residual errors are usually assumed, but such assumptions make inferences vulnerable to the presence of outliers. Motivated by a concern of sensitivity to potential outliers or data with tails longer-than-normal, we aim to develop in this dissertation inference for linear and nonlinear mixed effects models with censored response (NLMEC/LMEC) based on the multivariate Student-t distribution, being a flexible alternative to the use of the corresponding normal distribution. We propose an ECM algorithm for computing the maximum likelihood estimates for NLMEC/LMEC. This algorithm uses closed-form expressions at the E-step, which relies on formulas for the mean and variance of a truncated multivariate-t distribution. The proposed algorithm is implemented in the R package tlmec. We also propose here an exact ECM algorithm for linear and nonlinear mixed effects models with censored response based on the multivariate normal distribution, which enable us to developed local influence analysis for mixed effects models on the basis of the conditional expectation of the complete-data log-likelihood function. The developed procedures are illustrated with two case studies, involving the analysis of longitudinal HIV viral load in two recent AIDS studies
Mestrado
Estatistica
Mestre em Estatística
48
Qi, Meng. "Development in Normal Mixture and Mixture of Experts Modeling". UKnowledge, 2016. http://uknowledge.uky.edu/statistics_etds/15.
Pełny tekst źródłaStreszczenie:
In this dissertation, first we consider the problem of testing homogeneity and order in a contaminated normal model, when the data is correlated under some known covariance structure. To address this problem, we developed a moment based homogeneity and order test, and design weights for test statistics to increase power for homogeneity test. We applied our test to microarray about Down’s syndrome. This dissertation also studies a singular Bayesian information criterion (sBIC) for a bivariate hierarchical mixture model with varying weights, and develops a new data dependent information criterion (sFLIC).We apply our model and criteria to birth- weight and gestational age data for the same model, whose purposes are to select model complexity from data.
49
Pham, Thanh Vinh. "The performance of Multilevel Structural Equation Modeling (MSEM) in comparison to Multilevel Modeling (MLM) in multilevel mediation analysis with non-normal data". Scholar Commons, 2017. http://scholarcommons.usf.edu/etd/7077.
Pełny tekst źródłaStreszczenie:
The mediation analysis has been used to test if the effect of one variable on another variable is mediated by the third variable. The mediation analysis answers a question of how a predictor influences an outcome variable. Such information helps to gain understanding of mechanism underlying the variation of the outcome. When the mediation analysis is conducted on hierarchical data, the structure of data needs to be taken into account. Krull and MacKinnon (1999) recommended using Multilevel Modeling (MLM) with nested data and showed that the MLM approach has more power and flexibility over the standard Ordinary Least Squares (OLS) approach in multilevel data. However the MLM mediation model still has some limitations such as incapability of analyzing outcome variables measured at the upper level. Preacher, Zyphur, and Zhang (2010) proposed that the Multilevel Structural Equation Modeling (MSEM) will overcome the limitation of MLM approach in multilevel mediation analysis. The purpose of this study was to examine the performance of the MSEM approach on non-normal hierarchical data. This study also aimed to compare the MSEM method with the MLM method proposed by MacKinnon (2008) and Zhang, Zyphur, and Preacher (2009). The study focused on the null hypothesis testing which were presented by Type I error, statistical power, and convergence rate. Using Monte Carlo method, this study systematically investigates the effect of several factors on the performance of the MSEM and MLM methods. Designed factors considered were: the magnitude of the population indirect effect, the population distribution shape, sample size at level 1 and level 2, and the intra-class correlation (ICC) level. The results of this study showed no significant effect of the degree of non-normality on any performance criteria of either MSEM or MLM models. While the Type I error rates of the MLM model reached the expected alpha level as the group number was 300 or higher, the MSEM model showed very conservative performance in term of controlling for the Type I error with the rejection rates of null conditions were zero or closed to zero across all conditions. It was evident that the MLM model outperformed the MSEM model in term of power for most simulated conditions. Among the simulation factors examined in this dissertation, the mediation effect size emerged as the most important one since it is highly associated with each of the considered performance criteria. This study also supported the finding of previous studies (Preacher, Zhang, & Zyphur, 2011; Zhang, 2005) about the relationship between sample size, especially the number of group, and the performance of either the MLM or MSEM models. The accuracy and precision of the MLM and MSEM methods were also investigated partially in this study in term of relative bias and confidence interval (CI) width. The MSEM model outperformed the MLM model in term of relative bias while the MLM model had better CI width than the MSEM model. Sample size, effect size, and ICC value were the factors that significantly associate with the performance of these methods in term of relative bias and CI width.
50
Maehara, Sánchez Rocío Paola 1983. "Modelo de regressão linear Sinh-Normal : Aplicações à tempo de vidas". [s.n.], 2014. http://repositorio.unicamp.br/jspui/handle/REPOSIP/307090.
Pełny tekst źródłaStreszczenie:
Orientador: Filidor Edilfonso Vilca LabraDissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Matemática Estatística e Computação Científica
Made available in DSpace on 2018-08-24T22:21:27Z (GMT). No. of bitstreams: 1 MaeharaSanchez_RocioPaola_M.pdf: 3392400 bytes, checksum: 820e10611571e2e9984d25f94c00ced2 (MD5) Previous issue date: 2014
Resumo: A família de distribuições Sinh-Normal é uma classe de distribuições simétricas com três parâmetros, e devido à presença destes parâmetros esta família é flexível. Quando a distribuição Sinh-Normal é unimodal, esta distribuição pode ser utilizada em lugar da distribuição normal, e consequentemente nos modelos de regressão. Uma subclasse das distribuições é o log-transformação da distribuição de tempo de fadiga Birnbaum-Saunders. Assim, várias propriedades da distribuição Birnbaum-Saunders e algumas generalizações podem ser obtidas. O principal objetivo deste trabalho é estudar alguns aspectos de estimação e análise de diagnóstico no modelo de regressão Sinh-Normal. A análise de diagnóstico baseia-se na metodologia de Cook (1986). Duas análises de dados são realizadas para ver como o modelo proposto pode ser utilizado na prática. Além disso, investigamos um teste de homogeneidade dos parâmetros de forma no modelo de regressão Sinh-Normal. Obtemos as estatísticas de escore para este teste. Finalmente, um exemplo numérico é apresentado para ilustrar a metodologia e as propriedades das estatísticas escore são investigadas através de simulações de Monte Carlo
Abstract: The family of Sinh-normal distributions is a class of symmetric distributions with three parameters, and due to presence of these parameters it is a very flexible distribution. When the Sinh-normal distribution is unimodal, it distribution could be used in place of the normal distribution and consequently in regression model. A subclass de distribution of Sinh-normal distributions is the log-transformation of the Birnbaum-Saunders fatigue-time distribution. So, several properties of the Birnbaum-Saunders distribution and some generalization can be obtained. The main objective of work is to study some aspect of estimation and analysis of diagnostics in the Sinh-Normal regression model. The analysis of diagnostics is based on the Cook (1986) approach. Two data analysis is performed to see how the proposed model can be used in practice. Furthermore, we investigate a test of homogeneity for shape parameters in the Sin-Normal regression model. We obtain the score statistics for such test. Finally, a numerical example is given to illustrate our methodology and the properties of the score statistics is investigated through Monte Carlo simulations
Mestrado
Estatistica
Mestra em Estatística