Type I Error Rates of the Kenward-Roger Adjusted Degree of Freedom F-test for a Split-Plot Design with Missing Values

Type I Error Rates of the Kenward-Roger F-test for a Split-Plot Design with Missing Values and Non- Normal Data

Type I Error Rates For A One Factor Within-Subjects Design With Missing Values.

Missing data are a common problem in educational research. A promising technique, that can be implemented in SAS PROC MIXED and is therefore widely available, is to use maximum likelihood to estimate model parameters and base hypothesis tests on these estimates. However, it is not clear which test statistic in PROC MIXED performs better with missing data. The performance of the Hotelling-Lawley...

Comparing denominator degrees of freedom approximations for the generalized linear mixed model in analyzing binary outcome in small sample cluster-randomized trials

BACKGROUND Small number of clusters and large variation of cluster sizes commonly exist in cluster-randomized trials (CRTs) and are often the critical factors affecting the validity and efficiency of statistical analyses. F tests are commonly used in the generalized linear mixed model (GLMM) to test intervention effects in CRTs. The most challenging issue for the approximate Wald F test is the ...

Kenward-Roger approximation for linear mixed models with missing covariates

Partially observed variables are common in scientific research. Ignoring the subjects with partial information may lead to a biased and or inefficient estimators, and consequently any test based only on the completely observed subjects may inflate the error probabilities. Missing data issue has been extensively considered in the regression model, especially in the independently identically (IID...

Comparing two testing procedures in unbalanced two-way ANOVA models under heteroscedasticity‎: Approximate degree of freedom and parametric bootstrap approach

‎The classic F-test is usually used for testing the effects of factors in homoscedastic two-way ANOVA models‎. ‎However‎, ‎the assumption of equal cell variances is usually violated in practice‎. ‎In recent years‎, ‎several test procedures have been proposed for testing the effects of factors‎. ‎In this paper‎, ‎the two methods that are approximate degree of freedom (ADF) and parametric bootstr...