Exhibit 19-2
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.
-Refer to Exhibit 19-2. The mean and the standard deviation of the sampling distribution of the number of students who preferred to get out early are
A)50 and 30
B)60 and 30
C)50 and 5.478
D)60 and 5.478

Question

Quizplus · Accepted Answer

The mean of the sampling distribution is calculated as np, where n is the sample size (150) and p is the probability of preferring to get out early (80/150 = 0.5333). So, mean = 150 * 0.5333 = 80. The standard deviation is calculated as sqrt(np(1-p)), which is sqrt(150 * 0.5333 * 0.4667) = 5.478.

Exhibit 19-2 Students in Statistics Classes Were Asked Whether They Preferred a Preferred