Exam 18: Nonparametric Methods

Fifteen people were asked to indicate their preference for domestic versus imported cars. The following data showed their preferences. With $\alpha$ = 0.06, test for a significant difference in the preferences for cars. A "+" indicates a preference for imported cars.

Two groups of students were asked to rank the activities sponsored by the Student Government Association on campus. The following show their rankings. Determine the Spearman rank-correlation coefficient and test for a significant correlation with $\alpha$ = 0.05.

Exhibit 18-2 Students in statistics classes were asked whether they preferred a 10-minute break or to get out of class 10 minutes early. In a sample of 150 students, 40 preferred a 10-minute break, 80 preferred to get out 10 minutes early, and 30 had no preference. We want to determine if there is a difference in students' preferences. -If a null hypothesis that states that two populations are identical is rejected using a nonparametric test, then it is safe to assume that