A manager who is conducting a time study now needs an accuracy of ±0.1 minutes, rather than ±0.2 minutes as in the past. Because of this change in accuracy, the adequate sample size becomes
A) one-fourth as large.
B) one-half as large.
C) twice as large.
D) four times as large.
E) eight times as large.

Question

Quizplus · Accepted Answer

The sample size needed for a time study is inversely proportional to the square of the desired level of precision. Therefore, if the desired accuracy (precision) is doubled, the sample size must increase by a factor of 4 (2^2). So, the adequate sample size becomes four times as large.

A Manager Who Is Conducting a Time Study Now Needs