In constructing a 95 percent confidence interval,if you increase n to 4n,the width of your confidence interval will (assuming other things remain the same)be:
A) about 25 percent of its former width.
B) about two times wider.
C) about 50 percent of its former width.
D) about four times wider.

Question

Quizplus · Accepted Answer

Increasing the sample size n to 4n reduces the standard error by a factor of 1/2 (since standard error is inversely proportional to the square root of n), thus reducing the width of the confidence interval to about 50% of its former width.

In Constructing a 95 Percent Confidence Interval,if You Increase N