In the article “Zinc gluconate lozenges for treating the common cold in children:

a randomized controlled trial” published in the Journal of the American Medical Association (Macknin et al., 1998), the authors reported the percentages given in Table 7.29 for students with cold symptoms during treatment with zinc gluconate glycine lozenges (ZGG) or a placebo who experienced nausea during the treatment period. Use the information in Table 7.29 to answer the following questions.

(a) Let ???????? be the proportion of students taking the placebo that experienced nausea during the treatment period and ???????? the proportion of students taking the ZGG lozenges that experienced nausea during the treatment period. Test ????0 ∶ ???????? = ???????? at the ???? = 0.05 level.

(b) Compute the ????-value associated with the test in part (a).

(c) Compute a 95% confidence interval for ???????? − ????????.