The simulation study described in Section 6.3 evaluated the effect of heavy-tailed and skewed distributions on the level of significance and power of the t test and Wilcoxon rank sum test. Examine the results displayed in Table 6.13, and then answer the following questions.
a. What has a greater effect, if any, on the level of significance of the t test, skewness or heavy-tailness?
b. What has a greater effect, if any, on the level of significance of the Wilcoxon rank sum test, skewness or heavy-tailness?