Wilcoxon Si ned Ranks Test & Mann Whitne U Test Problems 1. Suppose we want to compare the effectiveness of two products("Brand X\" and \"Brand Y"). We find twelve volunteers and randomly allocate half of them to use Brand X, and the rest to use Brand Y. We then get them to rate the effectiveness of the product, on a ten-point scale (where "0" = "very ineffective" and "10" = "very effective"). Is there a significant difference in the rated effectiveness of the two products? Test at .05 level of significance