If the desired precision to estimate a mean is increased by a factor of four (for example,from 40 to 10)the sample size is increased by a factor of ____,all else equal.
A)30.0
B)4.0
C)16.0
D)2.0
E)32.0

Question

Quizplus · Accepted Answer

The sample size required for estimating a mean with a desired precision is inversely proportional to the square of the desired precision. So if the desired precision is increased by a factor of 4 (i.e., precision is decreased by a factor of 1/4), the required sample size is increased by a factor of 16 (i.e., square of 4). Hence, the answer is (C) 16.0.

If the Desired Precision to Estimate a Mean Is Increased