| Popis: |
SUMMARY Each subject in a study independently ranks a set of items, undergoes a treatment and afterwards ranks the same set of items. Two tests are proposed of the null hypothesis that the conditional distribution of each post-treatment ranking is symmetrically distributed about the corresponding preranking. The alternative hypothesis for each test is that the post-treatment rankings are more clustered about a particular idealized ranking than would be expected under the null hypothesis. The idea of the first test is to score each subject according to how close his post-ranking is to the idealized ranking, conditional on the distance from his post-ranking to his preranking. The second test controls for a possible additional trend towards a potentially confounding ranking, such as the rank order in which the items are presented. The methodology is applied to a data set where 38 students rank four styles of literary criticism, then undergo a course in literary appreciation and afterwards rank the same four styles of criticism. A brief power study is also presented. |
