For which one of the following situations would Kendall’s tau be appropriate? a) The Mohs scale rates the hardness of minerals. If one mineral can scratch another, it is judged….
How would you re-design this study?
Product testing. A company is producing and marketing new reading activities for elementary school children that it believes will improve reading comprehension scores. A researcher randomly assigns third graders to an eight-week program in which some will use these activities and others will experience traditional teaching methods. At the end of the experiment, both groups take a reading comprehension exam. Their scores are shown in the back-to-back stemand-leaf display.
a) Do these results suggest that the new activities are better? Test an appropriate hypothesis with a Wilcoxon (or Mann-Whitney) rank-sum test and state your conclusion.
b) How would you re-design this study? What nonparametric method would be appropriate then?