TABLE 10-10
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 π₁ and π₂ 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 10-10, 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

Quizplus · Accepted Answer

The formula for the estimated standard error of the difference between two sample proportions is:
SE(π1-π2) = sqrt [(π1(1-π1))/n1 + (π2(1-π2))/n2]
Plugging in the values from the problem, we get:
SE(π1-π2) = sqrt [((0.66)(0.34))/150 + ((0.6)(0.4))/160] = 0.055

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