On 2010-03-02, at 4:00 AM, [email protected] wrote: > I am trying to understand the assumptions for a permutation test and > figure out how to explain those to beginning students. (I am working > on a project to integrate resampling methods into the first course in > statistics.) I have received some help from Tim Hesterberg who gave > me the first definition of exchangeability I've seen. One question is > whether assumptions apply to randomized experiments or to using > permutation tests for survey sampling applications. In addition it > would be helpful to have some counterexamples where the assumptions > are NOT satisfied (and why).
One perspective is that it makes NO assumptions. It depends what you intend the resulting p-values to mean. If they are to be interpreted as probabilities, then, yes, exchangeability can be seen as an enabling assumption. On the other hand, seen only as a scale of typicality, the randomization/permutation p-values do not *assume* exchangeability so much as provide a test of it. -- Please avoid sending me Word or PowerPoint attachments. See <http://www.gnu.org/philosophy/no-word-attachments.html> _______________________________________________ [email protected] mailing list https://stat.ethz.ch/mailman/listinfo/r-sig-teaching
