What is it about?
Modeling the Two-Way Layout when there is extra variation in the latter s columns or blocks is discussed in an earlier publication by Clarke and Godolphin (1992) in Communications in Statistics Theory and Methods. In the study of frost trials of barley data, where the two-way layout the exact test for heteroscedasticity is appropriate, when there is potentially a covariate, the exact test is pitted against the asymptotic likelihood ratio test based on the residuals. The exact test is shown to be more powerful and has advantages over the asymptotic likelihood test based on the residuals since it has exact size.
Featured Image
Why is it important?
This test models heteroscedasticity in the Two-Way Layout even when there is only one observation per cell. The exact test can be employed when the data are balanced or unbalanced, and is better than the likelihood ratio test based on REML or restricted maximum likelihood counterpart.
Perspectives
There is an algorithm supplied which gives the exact F-test. While the concepts are straightforward there is some complex theory behind the test which is detailed in the earlier paper.
Dr Brenton R. Clarke
Murdoch University
Read the Original
This page is a summary of: Exact testing for heteroscedasticity in a two‐way layout in variety frost trials when incorporating a covariate, Australian & New Zealand Journal of Statistics, December 2023, Wiley,
DOI: 10.1111/anzs.12404.
You can read the full text:
Contributors
The following have contributed to this page
