TABLE 10-11
A corporation randomly selects 150 salespeople and finds that 66% who have never taken a self-improvement course would like such a course. The firm did a similar study 10 years ago in which 60% of a random sample of 160 salespeople wanted a self-improvement course. The groups are assumed to be independent random samples. Let π 1 and π 2 represent the true proportion of workers who would like to attend a self-improvement course in the recent study and the past study, respectively.
-Referring to Table 10-11, what is the estimated standard error of the difference between the two sample proportions?
A) 0.629
B) 0.500
C) 0.055
D) 0

Question

TABLE 10-11
A corporation randomly selects 150 salespeople and finds that 66% who have never taken a self-improvement course would like such a course. The firm did a similar study 10 years ago in which 60% of a random sample of 160 salespeople wanted a self-improvement course. The groups are assumed to be independent random samples. Let π 1  and π 2  represent the true proportion of workers who would like to attend a self-improvement course in the recent study and the past study, respectively.
-Referring to Table 10-11, what is the estimated standard error of the difference between the two sample proportions?
A) 0.629
B) 0.500
C) 0.055
D) 0

Quizplus · Accepted Answer

The formula for the estimated standard error of the difference between two sample proportions is 
√[(p1(1-p1))/n1 + (p2(1-p2))/n2]
Plugging in the values, we get 
√[(0.66(1-0.66))/150 + (0.6(1-0.6))/160] = 0.055. Therefore, the answer is C.

TABLE 10-11 A Corporation Randomly Selects 150 Salespeople and Finds That 66