A research firm needs to estimate within 3% the proportion of junior executives leaving large manufacturing companies within three years. A 0.95 degree of confidence is to be used. Several years ago,a study revealed that 21% of junior executives left their company within three years. To update this study,how many junior executives should be surveyed?
A)594
B)612
C)709
D)897

Question

Quizplus · Accepted Answer

To determine the sample size required, we can use the formula:

n = (Z^2 * p * q) / E^2

Where: 
Z = z-score for the degree of confidence (0.95) = 1.96 
p = proportion from previous study = 0.21 
q = 1 - p = 0.79 
E = maximum error = 0.03

Plugging in the values:

n = (1.96^2 * 0.21 * 0.79) / 0.03^2 = 708.98

Rounding up to the nearest whole number, we get a sample size of 709. Therefore, the correct answer is C.

A Research Firm Needs to Estimate Within 3% the Proportion