Tesi sul tema "Education – research – statistical methods"
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1
Corrado, Charles J. "Nonparametric statistical methods in financial market research". Diss., The University of Arizona, 1988. http://hdl.handle.net/10150/184608.
Testo completoAbstract (sommario):
This dissertation presents an exploration of the use of nonparametric statistical methods based on ranks for use in financial market research. Applications to event study methodology and the estimation of security systematic risk are analyzed using a simulation methodology with actual daily security return data. The results indicate that procedures based on ranks are more efficient than normal theory procedures currently in common use.
2
Richaud, de Minzi María Cristina. "New statistical methods for research in personality assessment". Pontificia Universidad Católica del Perú, 2013. http://repositorio.pucp.edu.pe/index/handle/123456789/99784.
Testo completoAbstract (sommario):
In the present work a review of the new multivariate techniques and why they appear especiallysuited to the personality research is presented. Emerging models of personality and advances in the measurement of personality and psychopathology suggest that research in this field has ente red a stage of advanced development. The past two decades have shown importan! developments in statistics and measurement. Refinement of multivariate statistics has been especially importan! in personality assessment because of the complexity of relations among personality variables. Multivariate procedures provide the opportunity to examine the complexity of these interactions by providing methods of analysis for multiple variables. On the other hand, structural equation modeling and multivariate techniques for analyzing categorical variables have been developed. Multidimensional scaling and item response theory are the last developments.En este trabajo se realiza una revisión de las nuevas técnicas estadísticas y de su utilidad para la investigación en personalidad. Los nuevos modelos y los avances en la medición de la personalidad y la psicopatología sugieren que la investigación en este campo y en su evaluación han entrado en un estadio avanzado de desarrollo. En las dos últimas décadas se han producido importantes desarrollos en estadística y medición. El refinamiento de las técnicas de análisis multivariado ha sido fundamental en la evaluación de la personalidad debido a la complejidad de las relaciones entre sus variables. Los procedimientos de análisis multivariado proveen la oportunidad de examinar la complejidad de esas interacciones a través de métodos de análisis para variables múltiples. Por otra parte, se han desarrollado los modelos de ecuaciones estructurales y técnicas multivariadas para analizar variables categóricas. Los últimos desarrollos corresponden al escalamiento multidimensional y a la teoría de la respuesta al ítem.
3
Grigas, Paul (Paul Edward). "Methods for convex optimization and statistical learning". Thesis, Massachusetts Institute of Technology, 2016. http://hdl.handle.net/1721.1/106683.
Testo completoAbstract (sommario):
Thesis: Ph. D., Massachusetts Institute of Technology, Sloan School of Management, Operations Research Center, 2016.This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.
Cataloged from student-submitted PDF version of thesis.
Includes bibliographical references (pages 219-225).
We present several contributions at the interface of first-order methods for convex optimization and problems in statistical machine learning. In the first part of this thesis, we present new results for the Frank-Wolfe method, with a particular focus on: (i) novel computational guarantees that apply for any step-size sequence, (ii) a novel adjustment to the basic algorithm to better account for warm-start information, and (iii) extensions of the computational guarantees that hold in the presence of approximate subproblem and/or gradient computations. In the second part of the thesis, we present a unifying framework for interpreting "greedy" first-order methods -- namely Frank-Wolfe and greedy coordinate descent -- as instantiations of the dual averaging method of Nesterov, and we discuss the implications thereof. In the third part of the thesis, we present an extension of the Frank-Wolfe method that is designed to induce near-optimal low-rank solutions for nuclear norm regularized matrix completion and, for more general problems, induces near-optimal "well-structured" solutions. We establish computational guarantees that trade off efficiency in computing near-optimal solutions with upper bounds on the rank of iterates. We then present extensive computational results that show significant computational advantages over existing related approaches, in terms of delivering low rank and low run-time to compute a target optimality gap. In the fourth part of the thesis, we analyze boosting algorithms in linear regression from the perspective modern first-order methods in convex optimization. We show that classic boosting algorithms in linear regression can be viewed as subgradient descent to minimize the maximum absolute correlation between features and residuals. We also propose a slightly modified boosting algorithm that yields an algorithm for the Lasso, and that computes the Lasso path. Our perspective leads to first-ever comprehensive computational guarantees for all of these boosting algorithms, which provide a precise theoretical description of the amount of data-fidelity and regularization imparted by running a boosting algorithm, for any dataset. In the fifth and final part of the thesis, we present several related results in the contexts of boosting algorithms for logistic regression and the AdaBoost algorithm.
by Paul Grigas.
Ph. D.
4
Hille, Kathryn Streeter. "Student Placement: A Multifaceted Methodological Toolkit". Ohio University / OhioLINK, 2019. http://rave.ohiolink.edu/etdc/view?acc_num=ohiou1573216693530411.
Testo completo
5
Snell, Kym Iris Erika. "Development and application of statistical methods for prognosis research". Thesis, University of Birmingham, 2015. http://etheses.bham.ac.uk//id/eprint/6259/.
Testo completoAbstract (sommario):
A pivotal component of prognosis research is the prediction of future outcome risk. This thesis applies, develops and evaluates novel statistical methods for development and validation of risk prediction (prognostic) models. In the first part, a literature review of published prediction models shows that the Cox model remains the most common approach for developing a model using survival data; however, this avoids modelling the baseline hazard and therefore restricts individualised predictions. Flexible parametric survival models are shown to address this by flexibly modelling the baseline hazard, thereby enabling individualised risk predictions over time. Clinical application reveals discrepant mortality rates for different hip replacement procedures, and identifies common issues when developing models using clinical trial data. In the second part, univariate and multivariate random-effects meta-analyses are proposed to summarise a model’s performance across multiple validation studies. The multivariate approach accounts for correlation in multiple statistics (e.g. C-statistic and calibration slope), and allows joint predictions about expected model performance in applied settings. This allows competing implementation strategies (e.g. regarding baseline hazard choice) to be compared and ranked. A simulation study also provides recommendations for the scales on which to combine performance statistics to best satisfy the between-study normality assumption in random-effects meta-analysis.
6
Ho, Lai Ping. "Application of statistical methods to problems in epidemiological research". HKBU Institutional Repository, 2003. http://repository.hkbu.edu.hk/etd_ra/454.
Testo completo
7
Kunz, Lauren Margaret. "Statistical Methods for Comparative Effectiveness Research of Medical Devices". Thesis, Harvard University, 2014. http://nrs.harvard.edu/urn-3:HUL.InstRepos:14226082.
Testo completoAbstract (sommario):
A recent focus in health care policy is on comparative effectiveness of treatments--from drugs to behavioral interventions to medical devices. Medical devices bring a unique set of challenges for comparative effectiveness research. In this dissertation, I develop statistical methods for comparative effectiveness estimation and illustrate the methodology in the context of three different medical devices. In chapter 2, I review approaches for causal inference in the context of observational cohort studies, utilizing a potential outcomes framework demonstrated using data for patients undergoing revascularization surgery with radial versus femoral artery access. Propensity score methods; G-computation; augmented inverse probability of treatment weighting; and targeted maximum likelihood estimation are implemented and their causal and statistical assumptions evaluated. In chapter 3, I undertake a theoretical and simulation-based assessment of differential follow-up information per treatment arm on inference in meta-analysis where applied researchers commonly assume similar follow-up duration across treatment groups. When applied to the implantation of cardiovascular resynchronization therapies to examine comparative survival, only 3 of 8 studies report arm-specific follow-up. I derive the bias of the rate ratio for an individual study using the number of deaths and total patients per arm and show that the bias can be large, even for modest violations of the assumption that follow-up is the same in the two arms. Furthermore, when pooling multiple studies with Bayesian methods for random effects meta-analysis, the direction and magnitude of the bias is unpredictable. In chapter 4, I examine the statistical power for designing a study of devices when it is difficult to blind patients and providers, everyone wants the device, and clustering by hospitals where the devices are implanted needs to be taken into account. In these situations, a stepped wedge design (SWD) cluster randomized design may be used to rigorously assess the roll-out of novel devices. I determine the exact asymptotic theoretical power using Romberg integration over cluster random effects to calculate power in a two-treatment, binary outcome SWD. Over a range of design parameters, the exact method is from 9% to 2.4 times more efficient than designs based on the existing method.
8
Vähänikkilä, H. (Hannu). "Statistical methods in dental research, with special reference to time-to-event methods". Doctoral thesis, Oulun yliopisto, 2015. http://urn.fi/urn:isbn:9789526207933.
Testo completoAbstract (sommario):
Abstract Statistical methods are an essential part of the published dental research. It is important to evaluate the use of these methods to improve the quality of dental research. In the first part, the aim of this interdisciplinary study is to investigate the development of the use of statistical methods in dental journals, quality of statistical reporting and reporting of statistical techniques and results in dental research papers, with special reference to time-to-event methods. In the second part, the focus is specifically on time-to-event methods, and the aim is to demonstrate the strength of time-to-event methods in collecting detailed data about the development of oral health. The first part of this study is based on an evaluation of dental articles from five dental journals. The second part of the study is based on empirical data from 28 municipal health centres in order to study variations in the survival of tooth health. There were different profiles in the statistical content among the journals. The quality of statistical reporting was quite low in the journals. The use of time-to-event methods has increased from 1996 to 2007 in the evaluated dental journals. However, the benefits of these methods have not been fully adopted in dental research. The current study added new information regarding the status of statistical methods in dental research. Our study also showed that complex time-to-event analysis methods can be utilized even with detailed information on each tooth in large groups of study subjects. Authors of dental articles might apply the results of this study to improve the study protocol/planning as well as the statistical section of their research articleTiivistelmä Tilastolliset tutkimusmenetelmät ovat olennainen osa hammaslääketieteellistä tutkimusta. Menetelmien käyttöä on tärkeä tutkia, jotta hammaslääketieteen tutkimuksen laatua voitaisiin parantaa. Tämän poikkitieteellisen tutkimuksen ensimmäisessä osassa tavoite on tutkia erilaisten tilastomenetelmien ja tutkimusasetelmien käyttöä, raportoinnin laatua ja tapahtumaan kuluvan ajan analysointimenetelmien käyttöä hammaslääketieteellisissä artikkeleissa. Toisessa osassa osoitetaan analysointimenetelmien vahvuus isojen tutkimusjoukkojen analysoinnissa. Ensimmäisen osan tutkimusaineiston muodostavat viiden hammaslääketieteellisen aikakauslehden artikkelit. Toisen osan tutkimusaineiston muodostivat 28 terveyskeskuksessa eri puolella Suomea hammashoitoa saaneet potilaat. Lehdet erosivat toisistaan tilastomenetelmien käytön ja tulosten esittämisen osalta. Tilastollisen raportoinnin laatu oli lehdissä puutteellinen. Tapahtumaan kuluvan ajan analysointimenetelmien käyttö on lisääntynyt vuosien 1996–2007 aikana. Tapahtumaan kuluvan ajan analysointimenetelmät mittaavat seuranta-ajan tietystä aloituspisteestä määriteltyyn päätepisteeseen. Tämän väitöksen tutkimukset osoittivat, että tapahtumaan kuluvan ajan analysointimenetelmät sopivat hyvin isojen tutkimusjoukkojen analysointiin. Menetelmien hyötyä ei ole kuitenkaan vielä saatu täysin esille hammaslääketieteellisissä julkaisuissa. Tämä tutkimus antoi uutta tietoa tilastollisten tutkimusmenetelmien käytöstä hammaslääketieteellisessä tutkimuksessa. Artikkelien kirjoittajat voivat hyödyntää tämän tutkimuksen tuloksia suunnitellessaan hammaslääketieteellistä tutkimusta
9
Elia, Eleni. "Statistical methods in prognostic factor research : application, development and evaluation". Thesis, University of Birmingham, 2017. http://etheses.bham.ac.uk//id/eprint/7259/.
Testo completoAbstract (sommario):
In patients with a particular disease or health condition, prognostic factors are characteristics (such as age, biomarkers) that are associated with different risks of a future clinical outcome. Research is needed to identify prognostic factors, but current evidence suggests that primary research is of low quality and poorly/selectively reported, which limits subsequent systematic reviews and meta-analysis. This thesis aims to improve prognostic factor research, through the application, development and evaluation of statistical methods to quantify the effect of potential prognostic factors. Firstly, I conduct a new prognostic factor study in pregnant women. The findings suggest that the albumin/creatinine ratio (ACR) is an independent prognostic factor for neonatal and, in particular, maternal composite adverse outcomes; thus ACR may enhance individualised risk prediction and clinical decision-making. Then, a literature review is performed to flag challenges in conducting meta-analysis of prognostic factor studies in the same clinical area. Many issues are identified, especially between-study heterogeneity and potential bias in the thresholds (cut-off points) used to dichotomise continuous factors, and the set of adjustment factors. Subsequent chapters aim to tackle these issues by proposing novel multivariate meta-analysis methods to ‘borrow strength’ across correlated thresholds and/or adjustment factors. These are applied to a variety of examples, and evaluated through simulation, which show how the approach can reduce bias and improve precision of meta-analysis results, compared to traditional univariate methods. In particular, the percentage reduction in the variance is of a similar magnitude to the percentage of data missing at random.
10
Roloff, Verena Sandra. "Statistical methods for using meta-analysis to plan future research". Thesis, University of Cambridge, 2012. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.610859.
Testo completo
11
Chiu, Jing-Er. "Applications of bayesian methods to arthritis research /". free to MU campus, to others for purchase, 2001. http://wwwlib.umi.com/cr/mo/fullcit?p3036813.
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12
Shearer, Sarah E. "ArchiTECHture: Rebuilding the Traditional University for the 21st Century". Scholarship @ Claremont, 2015. http://scholarship.claremont.edu/cmc_theses/1198.
Testo completoAbstract (sommario):
This senior thesis is an examination of the major complexities and considerations encountered in developing an e-learning program. In light of the changing landscape of higher education resulting from technological advancement, combined with changing pedagogies and financial pressures, traditional institutions are under heightened scrutiny and most in need of innovation. Online learning as been proposed as a solution to many of these issues, but creating a successful program is no small feat. Furthermore, experimental research on specific course designs and delivery often fails upon real-world implementation. Looking through the lens of Design-Base-Implementation Research (DBIR), an emerging research model that seeks to rectify this inefficiency, this thesis will first affirm the crucial need for active leadership throughout the development and implementation process. Analysis will then turn to the most pertinent elements administrators must address, including the motivations and catalysts for innovation, funding, faculty engagement, IT support, course design and project evaluation; in keeping with DBIR methodology, each of these considerations will take different forms and require alternative courses of action based on the unique institutional attributes and circumstances. Finally, the exploration will culminate in reasserting the urgency for innovation in higher education, and concluding that a uniform “solution” will not only be pragmatically impossible but also detrimental to both institutional legacy and student education: a quality and sustainable program necessitates due diligence in acknowledging and working with the distinct characteristics of each institution.
13
Miettunen, J. (Jouko). "Statistical methods in psychiatric research, with special reference on factor analysis". Doctoral thesis, University of Oulu, 2004. http://urn.fi/urn:isbn:9514273672.
Testo completoAbstract (sommario):
Abstract This interdisciplinary study describes in the first part the frequency with which various statistical research designs and methods are reported in psychiatric journals, and investigates how the use of these methods affect the visibility of the article in the form of received citations. In the second part focus is specifically on factor analysis, and the study presents two applications of this method. Original research articles (N = 448) from four general psychiatric journals in 1996 were reviewed. The journals were the American Journal of Psychiatry, the Archives of General Psychiatry, the British Journal of Psychiatry and the Nordic Journal of Psychiatry. There were differences in the utilisation of statistical procedures among the journals. The use of statistical methods was not strongly associated with the further utilisation of an article. However, extended description of statistical procedures had a positive effect on the received citations. Factor analysis is a statistical method based on correlations of the variables, which is often used when validity and structure of psychiatric instruments are studied. Exploratory factor analysis is designed to explore underlying latent factors, and in confirmatory factor analysis the aim is to verify the factor structure based on earlier findings in other data sets. Using data from the 31-year follow-up of the Northern Finland 1966 Birth Cohort Study this study aimed to demonstrate the validity and factor structure of scales measuring temperament (Tridimensional Personality Questionnaire, TPQ, and Temperament and Character Inventory, TCI) and alexithymia (20-item Toronto Alexithymia Scale, TAS-20). The results of exploratory factor analysis indicated good performance of the TCI and TPQ, though the results suggested that some developmental work is still needed. Of the two scales, the TCI worked psychometrically better than the TPQ. A confirmatory factor analysis showed that the three-factor model of TAS-20 was in agreement with the Finnish version of the scale. To conclude, future authors of psychiatric journals might apply these results in designing their research to present intelligible and compact analysis combined with a high quality presentation technique. Results of the factor analyses showed that the TPQ, TCI and TAS-20 can be used also in their Finnish versionsTiivistelmä Tämä poikkitieteellinen tutkimus kuvaa erilaisten tilastotieteellisten menetelmien yleisyyttä ja merkitystä psykiatriassa. Tutkimuksen ensimmäisessä osassa tutkitaan erilaisten tilastomenetelmien ja tutkimusasetelmien osuutta psykiatrisissa artikkeleissa ja lisäksi käytettyjen menetelmien vaikutusta artikkelien saamien viittausten lukumäärään. Tutkimuksen toisessa osassa keskitytään faktorianalyysiin ja esitetään kaksi siihen liittyvää sovellusta. Aineiston muodostavat alkuperäistuloksia esittelevät artikkelit (N = 448) neljästä eri psykiatrian tieteellisestä yleislehdestä vuodelta 1996. Kyseiset lehdet ovat American Journal of Psychiatry, Archives of General Psychiatry, British Journal of Psychiatry ja Nordic Journal of Psychiatry. Lehdet erosivat toisistaan tilastotieteellisten menetelmien käytössä ja tulosten esittämisessä. Tilastotieteellisten menetelmien käytöllä ei ollut suurta vaikutusta artikkelien saamien viittausten lukumäärään, mutta laajalla menetelmien kuvauksella oli positiivinen vaikutus viittausten lukumäärään. Faktorianalyysi on tilastotieteellinen tutkimusmenetelmä, jota käytetään tutkittaessa millaisista osatekijöistä erilaiset monimutkaiset ilmiöt koostuvat. Erityisesti tutkittaessa psykiatristen mittareiden validiteettia ja rakennetta faktorianalyysi on osoittautunut hyödylliseksi. Eksploratiivisessa faktorianalyysissa tarkoituksena on etsiä taustalla olevia piileviä muuttujia ja konfirmatorisessa faktorianalyysissa tarkoitus on vahvistaa aiemmissa tutkimuksissa todettu mittarin faktorirakenne. Tässä tutkimuksessa hyödynnetään aineistoa Pohjois-Suomen vuoden 1966 syntymäkohortin 31 vuoden seurannasta. Aineiston avulla tutkitaan temperamenttia (Tridimensional Personality Questionnaire, TPQ, ja Temperament and Character Inventory, TCI) ja aleksitymiaa (20-item Toronto Alexithymia Scale, TAS-20) tutkivien mittareiden suomenkielisten käännöksien validiteettia ja faktorirakennetta. Eksploratiivisen faktorianalyysin tulokset kertoivat, että TPQ ja TCI toimivat hyvin myös suomenkielellä. Kuitenkin mittareissa on vielä kehittämisen varaa. TCI:n psykometriset ominaisuudet olivat paremmat kuin TPQ:n. Aleksitymiamittarin TAS-20 konfirmatorinen faktorianalyysi osoitti että aiemmin julkaistu kolmen faktorin malli toimi hyvin myös suomalaisella versiolla. Psykiatristen artikkelien kirjoittajat voivat hyödyntää tämän tutkimuksen tuloksia suunnitellessaan psykiatrista tutkimusta suuntaan, jossa selkeä ja tiivis tulosten analysointitapa ja korkealaatuinen tulosten esitystapa korostuu. Faktorianalyysi soveltuu hyvin mittarin validiteetin tutkimiseen. Tutkimus osoitti TPQ-, TCI- ja TAS-20-mittareiden suomenkielisten versioiden validiteetin
14
Cefalu, Matthew Steven. "Statistical Methods for Effect Estimation in Biomedical Research: Robustness and Efficiency". Thesis, Harvard University, 2013. http://dissertations.umi.com/gsas.harvard:10850.
Testo completoAbstract (sommario):
Practical application of statistics in biomedical research is predicated on the notion that one can readily return valid effect estimates of the health consequences of treatments (exposures) that are being studied. The goal as statisticians should be to provide results that are scientifically useful, to use the available data as efficiently as possible, to avoid unnecessary assumptions, and, if necessary, develop methods that are robust to incorrect assumptions. In this dissertation, I provide methods for effect estimation that meet these goals. I consider three scenarios: (1) clustered binary outcomes; (2) continuous outcomes with a binary treatment; and (3) continuous outcomes with potentially missing continuous exposure. In each of these settings, I discuss the shortfalls of current statistical methods for effect estimation available in the literature and propose new and innovative methods that meet the previously stated goals. The validity of each proposed estimator is theoretically verified using asymptotic arguments, and the finite sample behavior is studied through simulation.
15
Wu, Chi-Hung Evelyn. "Causal analysis of highway crashes : a systematic analysis approach with subjective and statistical methods". Diss., Georgia Institute of Technology, 2001. http://hdl.handle.net/1853/20030.
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Man, Peter Lau Weilen. "Statistical methods for computing sensitivities and parameter estimates of population balance models". Thesis, University of Cambridge, 2013. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.608291.
Testo completo
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Jinn, Nicole Mee-Hyaang. "Toward Error-Statistical Principles of Evidence in Statistical Inference". Thesis, Virginia Tech, 2014. http://hdl.handle.net/10919/48420.
Testo completoAbstract (sommario):
The context for this research is statistical inference, the process of making predictions or inferences about a population from observation and analyses of a sample. In this context, many researchers want to grasp what inferences can be made that are valid, in the sense of being able to uphold or justify by argument or evidence. Another pressing question among users of statistical methods is: how can spurious relationships be distinguished from genuine ones? Underlying both of these issues is the concept of evidence. In response to these (and similar) questions, two questions I work on in this essay are: (1) what is a genuine principle of evidence? and (2) do error probabilities have more than a long-run role? Concisely, I propose that felicitous genuine principles of evidence should provide concrete guidelines on precisely how to examine error probabilities, with respect to a test's aptitude for unmasking pertinent errors, which leads to establishing sound interpretations of results from statistical techniques. The starting point for my definition of genuine principles of evidence is Allan Birnbaum's confidence concept, an attempt to control misleading interpretations. However, Birnbaum's confidence concept is inadequate for interpreting statistical evidence, because using only pre-data error probabilities would not pick up on a test's ability to detect a discrepancy of interest (e.g., "even if the discrepancy exists" with respect to the actual outcome. Instead, I argue that Deborah Mayo's severity assessment is the most suitable characterization of evidence based on my definition of genuine principles of evidence.Master of Arts
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Boyer, Christopher A. (Christopher Andrew). "Statistical methods for forecasting and estimating passenger willingness-to-pay in airline revenue management". Thesis, Massachusetts Institute of Technology, 2010. http://hdl.handle.net/1721.1/61191.
Testo completoAbstract (sommario):
Thesis (S.M.)--Massachusetts Institute of Technology, Sloan School of Management, Operations Research Center, 2010.Page 170 blank. Cataloged from PDF version of thesis.
Includes bibliographical references (p. 167-169).
The emergence of less restricted fare structures in the airline industry reduced the capability of airlines to segment demand through restrictions such as Saturday night minimum stay, advance purchase, non-refundability, and cancellation fees. As a result, new forecasting techniques such as Hybrid Forecasting and optimization methods such as Fare Adjustment were developed to account for passenger willingness-to- pay. This thesis explores statistical methods for estimating sell-up, or the likelihood of a passenger to purchase a higher fare class than they originally intended, based solely on historical booking data available in revenue management databases. Due to the inherent sparseness of sell-up data over the booking period, sell-up estimation is often difficult to perform on a per-market basis. On the other hand, estimating sell-up over an entire airline network creates estimates that are too broad and over-generalized. We apply the K-Means clustering algorithm to cluster markets with similar sell-up estimates in an attempt to address this problem, creating a middle ground between system-wide and per-market sell-up estimation. This thesis also formally introduces a new regression-based forecasting method known as Rational Choice. Rational Choice Forecasting creates passenger type categories based on potential willingness-to-pay levels and the lowest open fare class. Using this information, sell-up is accounted for within the passenger type categories, making Rational Choice Forecasting less complex than Hybrid Forecasting. This thesis uses the Passenger Origin-Destination Simulator to analyze the impact of these forecasting and sell-up methods in a controlled, competitive airline environment. The simulation results indicate that determining an appropriate level of market sell-up aggregation through clustering both increases revenue and generates sell-up estimates with a sufficient number of observations. In addition, the findings show that Hybrid Forecasting creates aggressive forecasts that result in more low fare class closures, leaving room for not only sell-up, but for recapture and spill-in passengers in higher fare classes. On the contrary, Rational Choice Forecasting, while simpler than Hybrid Forecasting with sell-up estimation, consistently generates lower revenues than Hybrid Forecasting (but still better than standard pick-up forecasting). To gain a better understanding of why different markets are grouped into different clusters, this thesis uses regression analysis to determine the relationship between a market's characteristics and its estimated sell-up rate. These results indicate that several market factors, in addition to the actual historical bookings, may predict to some degree passenger willingness-to-pay within a market. Consequently, this research illustrates the importance of passenger willingness-to-pay estimation and its relationship to forecasting in airline revenue management.
by Christopher A. Boyer.
S.M.
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Wong, Chun-mei May, e 王春美. "Multilevel models for survival analysis in dental research". Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2005. http://hub.hku.hk/bib/B3637216X.
Testo completo
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Yang, Kit-ling, e 楊潔玲. "Statistical analysis of temporal and spatial variations in suicide data". Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2009. http://hub.hku.hk/bib/B42841811.
Testo completo
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Surujon, Defne. "Computational approaches in infectious disease research: Towards improved diagnostic methods". Thesis, Boston College, 2020. http://hdl.handle.net/2345/bc-ir:109089.
Testo completoAbstract (sommario):
Thesis advisor: Kenneth WilliamsDue to overuse and misuse of antibiotics, the global threat of antibiotic resistance is a growing crisis. Three critical issues surrounding antibiotic resistance are the lack of rapid testing, treatment failure, and evolution of resistance. However, with new technology facilitating data collection and powerful statistical learning advances, our understanding of the bacterial stress response to antibiotics is rapidly expanding. With a recent influx of omics data, it has become possible to develop powerful computational methods that make the best use of growing systems-level datasets. In this work, I present several such approaches that address the three challenges around resistance. While this body of work was motivated by the antibiotic resistance crisis, the approaches presented here favor generalization, that is, applicability beyond just one context. First, I present ShinyOmics, a web-based application that allow visualization, sharing, exploration and comparison of systems-level data. An overview of transcriptomics data in the bacterial pathogen Streptococcus pneumoniae led to the hypothesis that stress-susceptible strains have more chaotic gene expression patterns than stress-resistant ones. This hypothesis was supported by data from multiple strains, species, antibiotics and non-antibiotic stress factors, leading to the development of a transcriptomic entropy based, general predictor for bacterial fitness. I show the potential utility of this predictor in predicting antibiotic susceptibility phenotype, and drug minimum inhibitory concentrations, which can be applied to bacterial isolates from patients in the near future. Predictors for antibiotic susceptibility are of great value when there is large phenotypic variability across isolates from the same species. Phenotypic variability is accompanied by genomic diversity harbored within a species. I address the genomic diversity by developing BFClust, a software package that for the first time enables pan-genome analysis with confidence scores. Using pan-genome level information, I then develop predictors of essential genes unique to certain strains and predictors for genes that acquire adaptive mutations under prolonged stress exposure. Genes that are essential offer attractive drug targets, and those that are essential only in certain strains would make great targets for very narrow-spectrum antibiotics, potentially leading the way to personalized therapies in infectious disease. Finally, the prediction of adaptive outcome can lead to predictions of future cross-resistance or collateral sensitivities. Overall, this body of work exemplifies how computational methods can complement the increasingly rapid data generation in the lab, and pave the way to the development of more effective antibiotic stewardship practices
Thesis (PhD) — Boston College, 2020
Submitted to: Boston College. Graduate School of Arts and Sciences
Discipline: Biology
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Knutson, Anna V., e Merideth Garcia. "Ethics in Digital Research Methods". Digital Commons @ East Tennessee State University, 2019. https://dc.etsu.edu/etsu-works/5449.
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Boyd, Felicity T. "Methods of learning in statistical education design and analysis of a randomized trial /". Available to US Hopkins community, 2002. http://wwwlib.umi.com/dissertations/dlnow/3080628.
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Liang, Yiheng. "Computational Methods for Discovering and Analyzing Causal Relationships in Health Data". Thesis, University of North Texas, 2015. https://digital.library.unt.edu/ark:/67531/metadc804966/.
Testo completoAbstract (sommario):
Publicly available datasets in health science are often large and observational, in contrast to experimental datasets where a small number of data are collected in controlled experiments. Variables' causal relationships in the observational dataset are yet to be determined. However, there is a significant interest in health science to discover and analyze causal relationships from health data since identified causal relationships will greatly facilitate medical professionals to prevent diseases or to mitigate the negative effects of the disease. Recent advances in Computer Science, particularly in Bayesian networks, has initiated a renewed interest for causality research. Causal relationships can be possibly discovered through learning the network structures from data. However, the number of candidate graphs grows in a more than exponential rate with the increase of variables. Exact learning for obtaining the optimal structure is thus computationally infeasible in practice. As a result, heuristic approaches are imperative to alleviate the difficulty of computations. This research provides effective and efficient learning tools for local causal discoveries and novel methods of learning causal structures with a combination of background knowledge. Specifically in the direction of constraint based structural learning, polynomial-time algorithms for constructing causal structures are designed with first-order conditional independence. Algorithms of efficiently discovering non-causal factors are developed and proved. In addition, when the background knowledge is partially known, methods of graph decomposition are provided so as to reduce the number of conditioned variables. Experiments on both synthetic data and real epidemiological data indicate the provided methods are applicable to large-scale datasets and scalable for causal analysis in health data. Followed by the research methods and experiments, this dissertation gives thoughtful discussions on the reliability of causal discoveries computational health science research, complexity, and implications in health science research.
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Thomas, Clifford S. "From 'tree' based Bayesian networks to mutual information classifiers : deriving a singly connected network classifier using an information theory based technique". Thesis, University of Stirling, 2005. http://hdl.handle.net/1893/2623.
Testo completoAbstract (sommario):
For reasoning under uncertainty the Bayesian network has become the representation of choice. However, except where models are considered 'simple' the task of construction and inference are provably NP-hard. For modelling larger 'real' world problems this computational complexity has been addressed by methods that approximate the model. The Naive Bayes classifier, which has strong assumptions of independence among features, is a common approach, whilst the class of trees is another less extreme example. In this thesis we propose the use of an information theory based technique as a mechanism for inference in Singly Connected Networks. We call this a Mutual Information Measure classifier, as it corresponds to the restricted class of trees built from mutual information. We show that the new approach provides for both an efficient and localised method of classification, with performance accuracies comparable with the less restricted general Bayesian networks. To improve the performance of the classifier, we additionally investigate the possibility of expanding the class Markov blanket by use of a Wrapper approach and further show that the performance can be improved by focusing on the class Markov blanket and that the improvement is not at the expense of increased complexity. Finally, the two methods are applied to the task of diagnosing the 'real' world medical domain, Acute Abdominal Pain. Known to be both a different and challenging domain to classify, the objective was to investigate the optiniality claims, in respect of the Naive Bayes classifier, that some researchers have argued, for classifying in this domain. Despite some loss of representation capabilities we show that the Mutual Information Measure classifier can be effectively applied to the domain and also provides a recognisable qualitative structure without violating 'real' world assertions. In respect of its 'selective' variant we further show that the improvement achieves a comparable predictive accuracy to the Naive Bayes classifier and that the Naive Bayes classifier's 'overall' performance is largely due the contribution of the majority group Non-Specific Abdominal Pain, a group of exclusion.
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Hines, Sonia J. "Nurses' research literacy: A multi-methods exploration". Thesis, Queensland University of Technology, 2022. https://eprints.qut.edu.au/229970/1/Sonia_Hines_Thesis.pdf.
Testo completoAbstract (sommario):
This thesis explored the concept of nurses' research literacy – how nurses' read and understand research literature. Through two systematic reviews of the literature, a pilot study and a qualitative research study, insights were formed into how nurses perceive research and how improved research literacy could be facilitated. Forty registered nurses from around Australia shared their experiences of learning about, reading and using research which led to different ways of thinking about teaching research. A new intervention for increasing research literacy, using a language-based, genre-analysis approach, was developed and found to be feasible and effective.
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Bellara, Aarti P. "Effectiveness of Propensity Score Methods in a Multilevel Framework: A Monte Carlo Study". Scholar Commons, 2013. http://scholarcommons.usf.edu/etd/4635.
Testo completoAbstract (sommario):
Propensity score analysis has been used to minimize the selection bias in observational studies to identify causal relationships. A propensity score is an estimate of an individual's probability of being placed in a treatment group given a set of covariates. Propensity score analysis aims to use the estimate to create balanced groups, akin to a randomized experiment. This study used Monte Carlo methods to examine the appropriateness of using propensity score methods to achieve balance between groups on observed covariates and reproduce treatment effect estimates in multilevel studies. Specifically, this study examined the extent to which four different propensity score estimation models and three different propensity score conditioning methods produced balanced samples and reproduced the treatment effects with clustered data. One single-level logistic model and three multilevel models were investigated. Conditioning methods included: (a) covariance adjustment, (b) matching, and (c) stratification. Design factors investigated included: (a) level-1sample size, (b) level-2 sample size, (c) level-1 covariate relationship to treatment, (d) level-2 covariate relationship to treatment, (e) level-1 covariate relationship to outcome, (f) level-2 covariate relationship to outcome, and (g) population effect size. The results of this study suggest the degree to which propensity score analyses are able to create balanced groups and reproduce treatment effect estimates with clustered data is largely dependent upon the propensity score estimation model and conditioning method selected. Overall, the single-level logistic and random intercepts models fared slightly better than the more complex multilevel models while covariance adjustment and matching methods tended to be more stable in terms of balancing groups than stratification. Additionally, the results indicate propensity score analysis should not be conducted with small samples. Finally, this study did not identify an estimation model or conditioning method that was consistently able to create adequately balanced groups and reproduce treatment effect estimates.
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Jimenez, Castro Jorge Alfonso. "Analysis of data from field plot experiments using models for spatial covariance and yield response". Thesis, University of Reading, 1992. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.306463.
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Keller, Rachel Elizabeth. "Failure to Reject the p-value is Not the Same as Accepting it: The Development, Validation, and Administration of the KPVMI Instrument". Diss., Virginia Tech, 2019. http://hdl.handle.net/10919/100743.
Testo completoAbstract (sommario):
The purpose of this study was to investigate on a national scale the baseline level of p-value fluency of future researchers (i.e., doctoral students). To that end, two research questions were investigated. The first research question, Can a sufficiently reliable and valid measure of p-value misinterpretations (in a research context) be constructed?, was addressed via the development and validation of the Keller P-value Misinterpretation Inventory instrument (KPVMI). An iterative process of expert review, pilot testing, and field testing resulted in an adequately reliable measure (Alpha = .8030) of p-value fluency as assessed across 18 misinterpretations and 2 process levels as well as an independently validated sub-measure of p-value fluency in context as assessed across 18 misinterpretations (Alpha = .8298). The second research question, What do the results of the KPVMI administration tell us about the current level of p-value fluency among doctoral students nationally?, was addressed via analysis of a subset of the field test data (n = 147) with respect to performance on the subset of items considered sufficiently validated as developed in Phases I-III (KPVMI-1). The median score was 10/18 items answered correctly indicating that future researchers on the aggregate struggle to properly interpret and report p-values in context; furthermore, there was insufficient evidence to indicate training and experience are positively correlated with performance. These results aligned with the extant literature regarding the p-value misinterpretations of practicing researchers.Doctor of Philosophy
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Neequaye, Beryl Koteikor. "Reviewing the Quality of Mixed Methods Research Reporting in Comparative and International Education: A Mixed Methods Research Synthesis". Ohio University / OhioLINK, 2019. http://rave.ohiolink.edu/etdc/view?acc_num=ohiou1565886346044592.
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Ohashi, Hideaki. "Design and Analysis of Allocation Methods for Peer Assessment in Education". Kyoto University, 2020. http://hdl.handle.net/2433/253412.
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Miller, Michael Chad. "Global Resource Management of Response Surface Methodology". PDXScholar, 2014. https://pdxscholar.library.pdx.edu/open_access_etds/1621.
Testo completoAbstract (sommario):
Statistical research can be more difficult to plan than other kinds of projects, since the research must adapt as knowledge is gained. This dissertation establishes a formal language and methodology for designing experimental research strategies with limited resources. It is a mathematically rigorous extension of a sequential and adaptive form of statistical research called response surface methodology. It uses sponsor-given information, conditions, and resource constraints to decompose an overall project into individual stages. At each stage, a "parent" decision-maker determines what design of experimentation to do for its stage of research, and adapts to the feedback from that research's potential "children", each of whom deal with a different possible state of knowledge resulting from the experimentation of the "parent". The research of this dissertation extends the real-world rigor of the statistical field of design of experiments to develop an deterministic, adaptive algorithm that produces deterministically generated, reproducible, testable, defendable, adaptive, resource-constrained multi-stage experimental schedules without having to spend physical resource.
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Goodpaster, Aaron M. "Statistical Analysis Methods Development for Nuclear Magnetic Resonance and Liquid Chromatography/Mass Spectroscopy Based Metabonomics Research". Miami University / OhioLINK, 2011. http://rave.ohiolink.edu/etdc/view?acc_num=miami1312317652.
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Austin, Erin, e L. Lee Glenn. "Online and Face-To-Face Orthopaedic Surgery Education Methods". Digital Commons @ East Tennessee State University, 2012. https://dc.etsu.edu/etsu-works/7497.
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So, Moon-tong, e 蘇滿堂. "Applications of Bayesian statistical model selection in social scienceresearch". Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2007. http://hub.hku.hk/bib/B39312951.
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Joshi, Shirish. "Statistical analysis and validation procedures under the common random number correlation induction strategy for multipopulation simulation experiments". Thesis, This resource online, 1991. http://scholar.lib.vt.edu/theses/available/etd-02132009-170935/.
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White, Beth. "Interdisciplinary Research Experiences For Undergraduates: Two Mixed-Methods Studies". ScholarWorks @ UVM, 2017. http://scholarworks.uvm.edu/graddis/675.
Testo completoAbstract (sommario):
Despite the demand for a diverse STEM-educated population and workforce, college students have consistently turned away from these disciplines in large numbers, creating a persistent problem that many are trying to address. The aim of the National Science Foundation's Research Experiences for Undergraduates (REU) program is to inspire, attract, and retain STEM majors. Funding supports undergraduate STEM students' engagement in real-world research alongside STEM mentors. As colleges and universities compete for funding for REUs, it is important to understand the mechanisms within summer research programs that resonate most deeply with undergraduate STEM researchers. While many studies reveal strong correlations between research experiences and STEM aspirations, less is known about the mechanisms within REU programs that support these gains. My research used quantitative and qualitative self-reported data from 20 REU students, 18 of whom were underrepresented minorities in STEM. Over two summers, these students, in cohorts of ten, came to the University of Vermont to participate in a team-oriented, 10-week REU: Interdisciplinary Research on Human Impacts in the Lake Champlain Ecosystem.
Two mixed-methods studies, guided by the frameworks of the theory of possible selves, theory of self-efficacy for research, and social cognitive career theory, revealed four important program mechanisms that gave rise to gains in research skills, confidence and self-efficacy for research, and STEM career aspirations, particularly for individuals from underrepresented minority groups in STEM. Findings suggest that the program fostered student capacity building within a safe, inclusive, and positive setting where students experienced what it feels like to be an active participant in the world of research. Within this context, critical mechanisms that gave rise to gains in research skills, confidence and self-efficacy for research, and STEM career aspirations included: (1) experiential education through interdisciplinary research experiences, (2) student independence and ownership balanced with expert researcher guidance and support, (3) formal and informal mentoring networks where students were mentored and where they mentored others, and (4) the establishment of an intentional learning community that advanced leadership, research skill building, perseverance, and reflection.
Results from this research cannot be generalized beyond the context of the Lake Champlain REU, however, findings are in alignment with the body of literature that highlights the positive effects of REUs on STEM majors' research skills, confidence and self-efficacy for research, and STEM career aspirations. Using mixed methods to identify and understand the within-program mechanisms that support student gains is a valuable new research approach for this field. Recognizing programmatic mechanisms across REU programs can lead to expansion, replication, and application of these models beyond one institution, resulting in more positive gains for more undergraduate STEM researchers.
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Doyle, Philip Gerard. "Developing statistical literacy with students and teachers in the secondary mathematics classroom". The University of Waikato, 2008. http://hdl.handle.net/10289/2324.
Testo completoAbstract (sommario):
This thesis investigates the teaching of statistical literacy in the first two years of secondary school mathematics. The teachers involved in the research aim to make changes to classroom practice in the teaching and learning of statistics and statistical literacy in response to changes in the New Zealand curriculum. An action research methodology is adopted by the research. A group of three teachers and the author undertake an action research cycle of planning, observing, acting and reflecting in three different Year 9 and 10 mathematics classrooms. The research documents the designing and implementing of strategies by a group of teachers in a mathematics department for integrating statistical literacy into teaching programmes. The research adopts framework for improving practice that utilise models for statistical literacy and thinking and principles for teaching with a language learning or literacy focus. Data is collected through discussions with teachers, observations of lessons and interviews with teachers and students. Themes emerge from the data. They include the significance of teacher and student concepts of statistics and statistical literacy, the importance of language and literacy in the statistics classroom, the adoption of teaching principles to facilitate statistical literacy and the challenge of adopting a critical literacy stance in the statistics classroom. The study highlights the importance of literacy and language skills in statistical literacy. The research concludes that the important changes needed for developing statistical literacy are about classroom methodology rather than content knowledge and shows that adoption of language learning principles into the teaching programme may achieve this.
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Rendina-Gobioff, Gianna. "Detecting publication bias in random effects meta-analysis : an empirical comparison of statistical methods". [Tampa, Fla] : University of South Florida, 2006. http://purl.fcla.edu/usf/dc/et/SFE0001494.
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Priestley, J. G. "Moral education and religious story : An essay in support of Whitehead's contention that the essence of education is that it be religious". Thesis, University of Exeter, 1988. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.380716.
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Wojtara-Perry, Shery. "The Impact of Transformational Leadership Style on the Success of Global Virtual Teams". ScholarWorks, 2016. https://scholarworks.waldenu.edu/dissertations/2180.
Testo completoAbstract (sommario):
Organizations in the age of modern technology have a diverse workforce, who are spread around the globe, and the business leaders of the 21st century need to understand how best to manage, overcome new challenges, and know the various skills of team members to capitalize on their differences and unique skills. To allow those geographically dispersed workers to reach their full potential and facilitate team success. Global virtual teams (GVTs) operate in complex environments characterized by diverse cultural and organizational elements. The primary purpose of this correlational and nonexperimental quantitative research was to examine the impact of transformational leadership on GVTs, their productivity, and job satisfaction with leadership effectiveness. Using the Multifactor Leadership Questionnaire (MLQ) and the Job Satisfaction Survey (JSS), data analyzes were completed through SurveyMonkey.com and SPSS software. The study measured transformational leadership, the independent variable, by the leader's ability to motivate workers to be satisfied and productive, and by the leader's effectiveness in the organization. Data were assessed by frequency analysis, moderation analyzes, and multiple regression analysis on the dependent variables of job satisfaction, leadership effectiveness, and productivity. The findings from this study reinforced the positive relationships found between transformational leadership, employee productivity, and leadership effectiveness in GVTs. Results also showed that motivated employees increase productivity and help in the organization's growth. Implications for positive social change included improvements in GVT interactions to increase the exchange of diverse ideas that lead to increased productivity and job satisfaction.
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Castellano, Escuder Pol. "Statistical methods for intake prediction and biological significance analysis in nutrimetabolomic studies". Doctoral thesis, Universitat de Barcelona, 2021. http://hdl.handle.net/10803/673827.
Testo completoAbstract (sommario):
This thesis is the product of three and a half years working on the complex world of metabolomics and nutrition. All the work presented here is focussed on the problems arising from associating and integrating metabolomics data with nutritional or dietary data. This issue has been approached using both observational and interventional studies and from a mainly bioinformatic point of view, proposing different methods and tools to reduce the complexity of nutrimetabolomics data analysis.
Thus, this work consists of four chapters divided into three parts, in addition to a summary of the content of the entire thesis in Catalan, the references, and the appendices. The first part consists of a global introduction, where the fundamental concepts needed for the correct understanding of the thesis are reviewed, as well as basic concepts about metabolomics and nutrition, the state of the art of the nutrimetabolomics field, and the fundamentals of biological significance analyses, among others. Then, this first part ends with a brief definition of the objectives of this work. In the second part, the results of this thesis are carefully presented and discussed. The results are presented in a compact format, with each section being a summary of a scientific publication. These results include the develompent of an ontology that defines the relationships between dietary metabolites and foods, the development of an open source tool for metabolomics data analysis, the development of an open source tool for nutrimetabolomics enrichment analysis, other open source tools developed in the context of this work, and a section with different publications where the methods and tools developed have been applied. Then, all these individual results are discussed together, providing a global and unified context where all the developments of this thesis are related. Lastly, the third part of this thesis presents the conclusions, contextualizing all the obtained results within the main objective of the thesis: contribute to the improvement of the integration and interpretation of nutrimetabolomics data. Additionally, in the appendices, the published results and some extra information used in carrying out this research are presented.
Finally, although this thesis is made up of contents from the fields of metabolomics, nutrition, bioinformatics and biostatistics, it has been written for a wide scientific audience, trying to be as comprehensible as possible for any profile of researchers, avoiding unnecessary complexities and always following the transversal objective of the thesis.
I hope you find it useful but, above all, that you enjoy reading it.
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Chen, Runqiu, e 陳潤球. "Statistical validation of kidney deficiency syndromes (KDS) and the development of a KDS questionnaire in Hong Kong Chinese women aged 40-60 years". Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2009. http://hub.hku.hk/bib/B43223813.
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Sheriff, Ray E. "Introducing Research Methods and Skills in a Workshop Environment". Higher Education Academy Engineering Subject Centre, 2007. http://hdl.handle.net/10454/3557.
Testo completoAbstract (sommario):
Yes`Research Seminar Series¿ is a 10-credit, Level M module offered to MSc/MEng students undertaking programmes in the areas of Electrical and Electronic Engineering at the University of Bradford. The module¿s aims are twofold: i) to disseminate stateoftheart information that could form the basis for future research programmes¿ and ii) to introduce the stages involved in the preparation and presentation of a research paper.
Higher Education Academy
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Ng, Yui-kin. "A critical analysis of the role of statistical significance testing in education research, with special attention to mathematics education". Thesis, Durham University, 2005. http://etheses.dur.ac.uk/2714/.
Testo completoAbstract (sommario):
This study analyzes the role of statistical significance testing (SST) in education. Although the basic logic underlying SST 一 a hypothesis is rejected because the observed data would be very unlikely if the hypothesis is true 一 appears so obvious that many people are tempted to accept it, it is in fact fallacious. In the light of its historical background and conceptual development, discussed in Chapter 2, the Fisher’s significance testing, Neyman-Pearson hypothesis testing and their hybrids are clearly distinguished. We argue that the probability of obtaining the observed or more extreme outcomes (p value) can hardly act as a measure of the strength of evidence against the null hypothesis. After discussing the five major interpretations of probability, we conclude that if we do not accept the subjective theory of probability, talking about the probability of a hypothesis that is not the outcome of a chance process is unintelligible. But the subjective theory itself has many intractable difficulties that can hardly be resolved. If we insist on assigning a probability value to a hypothesis in the same way as we assign one to a chance event, we have to accept that it is the hypothesis with low probability, rather than high probability, that we should aim at when conducting scientific research. More important, the inferences behind SST are shown to be fallacious from three different perspectives. The attempt to invoke the likelihood ratio with the observed or more extreme data instead of the probability of a hypothesis in defending the use of р value as a measure of the strength of evidence against the null hypothesis is also shown to be misleading because it can be demonstrated that the use of tail region to represent a result that is actually on the border would overstate the evidence against the ทน11 hypothesis.Although Neyman-Pearson hypothesis testing does not involve the concept of the probability of a hypothesis, it does have some other serious problems that can hardly be resolved. We show that it cannot address researchers' genuine concerns. By explaining why the level of significance must be specified or fixed prior to the analysis of data and why a blurring of the distinction between the р value and the significance level would lead to undesirable consequences, we conclude that the Neyman-Pearson hypothesis testing cannot provide an effective means for rejecting false hypotheses. After a thorough discussion of common misconceptions associated with SST and the major arguments for and against SST, we conclude that SST has insurmountable problems that could misguide the research paradigm although some other criticisms on SST are not really as justified. We also analyze various proposed alternatives to SST and conclude that confidence intervals (CIs) are no better than SST for the purpose of testing hypotheses and it is unreasonable to expect the existence of a statistical test that could provide researchers with algorithms or rigid rules by conforming to which all problems about testing hypotheses could be solved. Finally, we argue that falsificationism could eschew the disadvantages of SST and other similar statistical inductive inferences and we discuss how it could bring education research into a more fruitful situation in which to their practices. Although we pay special attention to mathematics education, the core of the discussion in the thesis might apply equally to other educational contexts.
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Chau, Ka-ki, e 周嘉琪. "Informative drop-out models for longitudinal binary data". Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2003. http://hub.hku.hk/bib/B2962714X.
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Coad, D. Stephen. "Outcome-dependent randomisation schemes for clinical trials with fluctuations in patient characteristics". Thesis, University of Oxford, 1989. http://ora.ox.ac.uk/objects/uuid:970a8103-24fc-496e-82c0-0645f2b4e9c4.
Testo completoAbstract (sommario):
A clinical trial is considered in which two treatments are to be compared. Treatment allocation schemes are usually designed to assign approximately equal numbers of patients to each treatment. The purpose of this thesis is to investigate the efficiency of estimation and the effect of instability in the response variable for allocation schemes which are aimed at reducing the number of patients who receive the inferior treatment. The general background to outcome-dependent allocation schemes is described in Chapter 1. A discussion of ethical and practical problems associated with these methods is presented together with brief details of actual trials conducted. In Chapter 2, the response to treatment is Bernoulli and the trial size is fixed. A simple method for estimating the treatment difference is proposed. Simulation results for a selection of allocation schemes indicate that the effect of instability upon the performance of the schemes can sometimes be substantial. A decision-theory approach is taken in Chapter 3. The trial is conducted in a number of stages and the interests of both the patients in the trial and those who will be treated after the end of the trial are taken into account. Using results for conditional normal distributions, analytical results are derived for estimation of the treatment difference for both a stable and an unstable normal response variable for three allocation schemes. Some results for estimation are also given for other responses. The problem of sequential testing is addressed in Chapter 4. With instability in the response variable, it is shown that the error probabilities for the test for a stable response variable can be approximately preserved by using a modified test statistic with appropriately-widened stopping boundaries. In addition, some recent results for estimation following sequential tests are outlined. Finally, the main conclusions of the thesis are highlighted in Chapter 5.
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李友榮 e Yau-wing Lee. "Modelling multivariate survival data using semiparametric models". Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2000. http://hub.hku.hk/bib/B4257528X.
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Long, Yongxian, e 龙泳先. "Semiparametric analysis of interval censored survival data". Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2010. http://hub.hku.hk/bib/B45541152.
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Adusei-Owusu, James. "Research projects". Thesis, Rhodes University, 2001. http://hdl.handle.net/10962/d1003624.
Testo completoAbstract (sommario):
RESEARCH PROJECTS: 1 RESEARCH PROJECT ONE: A literature review: Constructivism: An alternate approach to teaching and learning. Abstract The constructivist perspectives on learning have helped enhance science educators' understanding of how students make sense of their lived experiences. Constructivism purports to be a transformation of the traditional curriculum. As such this article starts with a brief overview of behaviorism: the scientific approach to education. The main tenets underlying constructivism, how constructivism guides educators to change their classroom practice, and the implications to science teaching have been reviewed. 2 RESEARCH PROJECT TWO (Empirical study): Being Constructive: College students' learning of work and heat as aspects of the energy concept based a constructivist approach. Abstract This study is an extension of a literature review on constructivism as an alternate teaching and learning approach discussed in research project one. It is an empirical study concerning the use of a learning module based on a constructivist approach to develop pre-service student teachers' understanding of work and heat as aspects of the energy concept. The data consisted mainly of transcripts of students' interviews, written responses to questionnaires designed in the form of a worksheet, and comments from non-participant observers and students. The results seem to suggest that a carefully designed learning module based on a constructivist teaching and learning approach may be a valuable tool in developing pre-service student teachers' understanding of work and heat. 3 RESEARCH PROJECT THREE (Empirical study): A College in transition: A case study of the readiness of a college in the Eastern Cape province to implement Outcomes-Based Education in an Education Development centre. Abstract Curriculum 2005 premised on Outcomes-Based Education is the new curriculum framework for South Africa. It signifies a paradigm shift in education from the traditional 'telling-listening' relationship between the teacher and the learner to one that emphasises leamer-centred approach to the teaching process. Teachers, though recognized as crucial to the educational transformation process in the country have also being identified as ill-equipped to meet the challenges posed by Outcomes-Based Education. This study starts with a brief overview of the South African curriculum and the main tenets underlying Outcomes-Based Education. The institutional conditions and whether the lecturers at a college in the Eastern Cape province perceive the need for a change in their classroom practice were also investigated. Bearing in mind the need for further research to validate the findings of this study, positive indicators that emerged from the study suggest the readiness of the college to implement Outcomes-Based Education at the proposed Education Development Centre.