On the correlation between f-ratios

The coefficient of correlation between noncentral F-ratios sharing a common denominator is given. The correlation between doubly dependent F-ratios is shown to be the correlation between singly dependent F-ratios times a function of the correlation between the F-ratios' numerators. The correlation is positive if at least one of the noncentrality parameters is zero, but may be zero or negative if both noncentrality parameters are positive. These relationships are viewed geometrically. Examples are taken from the NOVA in the unequal-cell-sizes case.     

Association Models for Multi-Dimensional Cross-Classifications of Ordinal Variables

Models are formulated for describing associations among ordinal variables in multidimensional tables.Uniform association and uniform interaction models occur as special cases in which equal-interval scores are assigned to levels of the variables.The models described are extensions of ones proposed by Goodman (1979).     

Some distributions arising from faulty inspection with multitype defectives,and an application to grading

Continuing their investigation of distributions arising from faulty and "incomplete" inspection from a finite popu-lation (Johnson et al. (1980), Comm. Statist.A9 917-922, Kotz and Johnson, ibid, All, 1997-2016) the authors investigate cases when inspection is not restricted to a single type of defect. Applications to grading problems, when grading is based on sets of defects found by sampling inspections, are indicated.     

Estimation from k independent randomly truncated samples: application to neutrino energies

We investigate estimation and testing procedures for the k-sample problem where each of the populations is subject to random truncation by possibly different but known truncation functions. Particular attention is focused on the two sample case which is motivated from the following important application. Neutrinos were detected from Supernova 1987A at two sites: the 1MB detector in Ohio (eight neutrinos observed) and the Kamiokande II detector in Japan (twelve observed). Each detector has different "trigger efficiencies", the chance of observing the flash of light produced by the neutrino knocking an electron loose from an atom. Thus, we have two independent samples of randomly truncated data. We assume a normal model for some power transformation of the data with the same power for each sample. We estimate the parameters of this distribution by maximum likelihood and find confidence regions for the parameters. A Monte Carlo study investigates the properties of the maximum likelihood estimators for this eutrino example.The simulations Show that approximate likelihood-based confidence regions provide coverages much closer to the nominal level than the regions based on asymptotic normal-theory.     

Efficient Semiparametric Bayesian Estimation of Multivariate Discrete Proportional Hazards Model with Random Effects

We incorporate a random effect into a multivariate discrete proportional hazards model and propose an efficient semiparametric Bayesian estimation method. By introducing a prior process for the parameters of baseline hazards, we consider a nonparametric estimation of baseline hazards function. Using a state space representation, we derive a dynamic modeling of baseline hazards function and propose an efficient block sampler for Markov chain Monte Carlo method. A numerical example using kidney patients data is given.     

Using observed confidence levels to perform principal component analyses

ABSTRACT

This paper focuses on applying the method of observed confidence levels to problems commonly encountered in principal component analyses. In particular, we focus on assigning levels of confidence to the number of components that explain a specified proportion of variation in the original data. Approaches based on the normal model as well as a non parametric model are explored. The usefulness of the methods are discussed using an example and an empirical study.     

New bootstrap confidence intervals for means of positively skewed distributions

ABSTRACT

In this paper, we consider the problem of constructing non parametric confidence intervals for the mean of a positively skewed distribution. We suggest calibrated, smoothed bootstrap upper and lower percentile confidence intervals. For the theoretical properties, we show that the proposed one-sided confidence intervals have coverage probability α + O(n^{? 3/2}). This is an improvement upon the traditional bootstrap confidence intervals in terms of coverage probability. A version smoothed approach is also considered for constructing a two-sided confidence interval and its theoretical properties are also studied. A simulation study is performed to illustrate the performance of our confidence interval methods. We then apply the methods to a real data set.     

A continuous-time Markov chain approach with the analytic likelihood in studies of behavioral changes

Abstract

We develop an analytic likelihood approach for a four-state CTMC by solving the backwards Kolmogorov differential equations, reducing this bias in transition rate estimates. A simulation study is performed to assess the performance of this new method and confirms that it achieves good coverage probabilities with low bias and standard errors. Finally, we analyzed data from Project SUCCESS to estimate the study each participant’s transitions among behavioral stage, consisting of risky drinking and possible ineffective using of contraception, which comprise the primary endpoint of risk of an alcohol-exposed pregnancy.