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Browse Dissertations and Theses  Statistics by Subject "Statistics"
Now showing items 2140 of 73

(1997)The joint consistency of item and ability parameter estimation remains a challenging problem in IRT parametric modeling. Although many simulation studies have been conducted on the item and ability parameter estimates ...
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(1995)The ordinary least squares (OLS) method is known to be efficient for linear models when the errors are homogeneous with Gaussian distributions, but troublesome with heteroscedastic or nonGaussian errors. For the latter ...
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(2003)The Markov chain marginal bootstrap (MCMB) is a new bootstrap method proposed by He and Hu (2002) for constructing confidence intervals or regions based on likelihood equations. It is designed to ease the computational ...
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(2004)Improved estimates of a survey population parameter can be obtained by using information about corelated auxiliary variable. There is a huge literature on such methods for estimating the mean. Here we explore some ...
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(1986)This thesis is devoted to constructing tests of hypotheses that dominate a given test which violates certain conditions such as convexity or monotonicity. Many authors, for example, Birnbaum (1955), Matthes and Truax (1967), ...
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(2006)The proposed test is motivated by studies of GeneChip data to identify differentially expressed genes through the analysis of probe level measurements. Realizing that the number of replicates is usually small in GeneChip ...
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(1990)Dimension reduction techniques are important in the problem of regression and prediction when the nominal number of predicting variables is greater than the number of observations. Two methods, principal components analysis ...
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(1989)A statistical procedure is developed with the purpose of detecting internal bias occurring concurrently in several items in an ability test. Concurrent internal bias (CIB) is considered in a nonparametric multidimensional ...
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(2005)Linear mixed models based on the normality assumption are widely used in health related studies. Although the normality assumption leads to simple, mathematically tractable, and powerful tests, violation of the assumption ...
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(2004)The reference growth charts are widely used to screen the measurements from an individual subject in the context of population values. The conventional reference growth charts are generated from crosssectional data and ...
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(2006)We illustrate the issues and methodology in the context of an immunogenicity study of measles vaccine for children as well as an ultrasound safety study of the occurrence and extent of lung hemorrhage in laboratory animals ...
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(2007)Longitudinal data are characterized by repeated measures over time on each subject. The generalized estimating equations (GEE) approach (Liang and Zeger, 1996) has been widely used for the analysis of longitudinal data. ...
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(2006)Marginal maximum likelihood estimation has become the standard for parameter estimation in latent variable models. However, there are instances when alternative estimators that jointly estimate incidental parameters and ...
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(2008)General computing algorithms are developed in R for the GEE computations and WinBugs to perform Gibbs sampling for the Bayesian analysis. Analyses of randomized controlled longitudinal data and randomized controlled surgical ...
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(1995)Unidimensionality is one of the most important assumptions required by much of the currently used item response theory (IRT) methodologies. In the first part of this thesis, a further and nontrivial practical refinement ...
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(1994)A new index based on the conditional covariance of item scores given a latent variable is defined and investigated to assess dimensionality in educational and psychological test data. This index successfully detects the ...
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(1995)Randles' one sample multivariate sign test based on interdirections is extended to two sample and multisample tests. A heuristic argument suggests that when samples are drawn from elliptically symmetric distributions all ...
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(1993)Efron (1988) proposes the use of standard logistic regression techniques to estimate hazard rates and survival curves from survival data. These techniques allow statisticians to use parametric regression modeling on survival ...
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Now showing items 2140 of 73