Cereal sugar. A food company is concerned about recent criticism of the sugar content of their children’s cereals. The data show the sugar content (as a percentage of weight) of several national brands of children’s and adults’

cereals. Are children’s cereals really different from adults’

cereals in sugar content? (Data in Cereal company)

Children’s cereals: 40.3, 55, 45.7, 43.3, 50.3, 45.9, 53.5, 43, 44.2, 44, 47.4, 44, 33.6, 55.1, 48.8, 50.4, 37.8, 60.3, 46.6 Adults’ cereals: 20, 30.2, 2.2, 7.5, 4.4, 22.2, 16.6, 14.5, 21.4, 3.3, 6.6, 7.8, 10.6, 16.2, 14.5, 4.1, 15.8, 4.1, 2.4, 3.5, 8.5, 10, 1, 4.4, 1.3, 8.1, 4.7, 18.4

a) Write the null and alternative hypotheses.

b) Check the conditions for a Wilcoxon rank-sum (or Mann-Whitney) test.

c) Complete the test and report your conclusion.

d) Make histograms of each group. Discuss whether you would choose a nonparametric test for these data or a two-sample t-test.