Problem 9.18 In a comparative study of the effectiveness of two brands of motion sickness pills, brand A pills were given to 45 persons randomly selected from a group of 90 air travelers while the other 45 persons were given brand B pills. The responses were classified as: None (no motion sickness), Slight (slight motion sickness), etc. None Slight Moderate Severe Total Brand A 18 17 6 4 45 Brand B 11 14 14 6 45 Total 29 31 20 10

(a) Give a careful description of the statistical test you would use to determine whether or not these two brands of pills differ significantly in effectiveness from one another. Identify the null and alternative hypotheses, the test statistic, its null distribution, and define the rejection region.

(b) Test your null hypothesis, described in part

(a) above, at the level α = 0.05.