Uniformly implementable small sample integrated likelihood ratio test for one-way and two-way ANOVA under heteroscedasticity and normality

AStA Advances in Statistical Analysis - ANOVA under normally distributed response and heteroscedastic variances is commonly encountered in biological, behavioral, educational and agricultural...     

Environmental sampling with a concomitant variable: a comparison between ranked set sampling and stratified simple random sampling

In many environmental sampling situations, the variable of interest is either not easily observable or is too expensive to observe. Under such circumstances, the need arises to observe another variable, related to the variable of interest, so as to estimate the population parameters of interest. We study the performance of two different sampling procedures, i.e. ranked set sampling and stratified simple random sampling, when both stratification and ranking are accomplished on the basis of such a concomitant variable. The relative precision of the two methods is obtained and expressed as a function of population variance, between-stratum and between-rank variation, and the correlation coefficient between the variable of interest and the concomitant variable. The relative precision is computed for several important families of distributions that occur frequently in environmental and ecological work. Under equal allocation of sampling units, stratified simple random sampling is found to perform better than ranked set sampling, when the costs incurred to obtain sample measurements are ignored. When optimum allocation is considered for both methods, ranked set sampling performs better than stratified simple random sampling, when the concomitant variable is not highly correlated with the variable of interest. Furthermore, when the costs of sampling and the costs of measurement are incorporated into the assessment of the relative precision, the ranked set sampling is seen to be more efficient than stratified simple random sampling, particularly when the cost of stratification is high compared with that of ranking. This is generally the case in practice.     

Economic design of non parametric sign control chart

An economic design of sign chart to control the median is proposed. Since the sign chart is distribution free, it can easily be applied to any process without prior knowledge of process quality distribution. The effect on loss cost observed for different shifts in location shows that the sign chart performs better for large shifts. The economic statistical performance study reveals that statistical performance of sign chart can be improved sufficiently for moderate shifts in the process. Sensitivity study shows that design is more sensitive for change in values of penalty loss cost and time required for search and repair of an assignable cause.     

Teaching Children With Autism Spectrum Disorder to Mand “Why?”

The Analysis of Verbal Behavior - For most children with autism spectrum disorder (ASD), manding for information is an important skill that must be systematically taught. Although previous studies...     

Teaching Children With Autism Spectrum Disorder to Mand “Why?”

For most children with autism spectrum disorder (ASD), manding for information is an important skill that must be systematically taught. Although previous studies have evaluated interventions for teaching other mands for information, to date no studies have demonstrated effective procedures for teaching the mand “why?” The purpose of the present study was to teach 3 children with ASD to mand “why?” under relevant establishing operation conditions in 3 distinct scenarios. A trial-unique multiple-exemplar procedure was used to promote generalization and increase the value of information provided across trials. All 3 participants learned to mand “why?” in all 3 scenarios within a mean of 18 sessions (range 14–21 sessions), demonstrated generalization to novel stimuli and settings, and maintained this skill over time. Social validity for the intervention had an overall mean of 5.88 (range 1–7).     

On Coloniality,Racialized Forgetting and the “Group Effect”: Interrogating Ethnic Studies' Meta-Narrative of Race

Against the backdrop of collaborative antiracist struggle, this paper considers knowledge about race constructed by contemporary ethnic studies. Examining narratives of self, history and purpose produced by ethnic studies, it argues that these narratives highlight processes of racialization at the level of received ethnic groups while eliding cross-group processes. It argues that the hyper-visibility of racialization at the level of distinct groups, coupled with the invisibility of cross-group processes, creates a “group effect” which has significant implications for alliance-building and solidarity. It ends with a discussion of some possibilities for countering the group effect.     

Table of percentage points of ratios of linear combinations of order statistics of samples from exponential distributions

A form of the distribution function of ratios of linear combinations of order statistics of samples from an exponential distribution is given. From the distribution, tables of percentage points of the statistic for α = .05, .95, and n = 3(1)50, and for censoring up to five observations are presented. Use of the tables is made to find critical values of the most powerful scale and location invariant test of exponentiality against uniformity, and also to find critical values for a test of outliers in an exponential population.     

A measure of asymmetry

It is a general practice to make assertions about the symmetry or asymmetry of a probability density function based on the coefficients of skewness. Since most of the coefficients of skewness are designed to be zero for a symmetric density, they overall do provide an indication of symmetry. However, skewness is primarily influenced by the tail behavior of a density function, and the skewness coefficients are designed to capture this behavior. Thus they do not calibrate asymmetry in the density curves. We provide a necessary condition for a probability density function to be symmetric and use that to measure asymmetry in a continuous density curve on the scale of ?1 to 1. We show through examples that the proposed measure does an admirable job of capturing the visual impression of asymmetry of a continuous density function.