In this paper we discuss the application of local influence in a measurement error regression model with null intercepts under a Student_t model with dependent populations. The Student_t distribution is a robust alternative to modelling data sets involving errors with longer than Normal tails....

We propose a U-statistics-based test for null variance components in linear mixed models and obtain its asymptotic distribution (for increasing number of units) under mild regularity conditions that include only the existence of the second moment for the random effects and of the fourth moment...

We consider the use of standard univariate and multivariate methods for profile analysis of randomized complete block experiments. Although the analysis for the case where the block time interaction is included in the model parallels that used for factorial experiments, situations where such...

In this paper the exponentiated-Weibull model is modified to model the possibility that long-term survivors are present in the data. The modification leads to an exponentiated-Weibull mixture model which encompasses as special cases the exponential and Weibull mixture models typically used to...

A Bayesian inference approach using Markov Chain Monte Carlo (MCMC) is developed for the logistic positive exponent (LPE) model proposed by Samejima and for a new skewed Logistic Item Response Theory (IRT) model, named Reflection LPE model. Both models lead to asymmetric item characteristic...

In this paper we propose a linear functional model with normal random effects and elliptical errors, thus extending the standard normal models considered previously. The corrected score approach (Nakamura, 1990) is used for parameter estimation and the resulting estimators are shown to be...

Very often, in psychometric research, as in educational assessment, it is necessary to analyze item response from clustered respondents. The multiple group item response theory (IRT) model proposed by Bock and Zimowski [12] provides a useful framework for analyzing such type of data. In this...