Exercise 2. The urinary fluoride concentration (ppm) was measured both for a sample of livestock that had been grazing in an area previously exposed to flouride pollution and for a similar sample that had grazed in an unpolluted region. Due to the smaller sample sizes and some evidence of nonnormality seen in the sample, the researchers plan to perform a Wilcoxon Rank-Sum/Mann-Whitney Test. Polluted 21.3, 18.7, 23.0, 17.1, 16.8, 20.9, 19.7 Unpolluted 14.2, 18.3, 17.2, 18.4, 20.0 a. What assumptions must be made for a Wilcoxon Rank-Sum/Mann-Whitney Test to be reasonable? b. Perform a Wilcoxon Rank-Sum/Mann-Whitney Test in R of the research hypotheses: HA : the distribution of urinary flouride concentrations in lifestock from polluted grazing pastures is the same as the distribution of urinary flouride concentrations in lifestock from unpolluted grazing pastures except for a shift to the right. Draw a conclusion at the o = 0.05 level in context