By what factor should the sample size in a poll be increased in order to cut the margin of error in half?
A)2
B)4
C)8
D)9

Question

Quizplus · Accepted Answer

According to the formula for margin of error, it is inversely proportional to the square root of the sample size (ME = 1/√n). Therefore, to cut the margin of error in half, we need to double the sample size. Since the sample size is in the denominator, this means we need to multiply it by 2² = 4. Hence, the answer is option B.

By What Factor Should the Sample Size in a Poll