A 90% confidence interval is constructed for the population mean. If a 95% confidence interval had been constructed instead (everything else remaining the same), the width of the interval would have been ________ and the probability of making an error would have been ________.
A) wider; bigger
B) wider; smaller
C) narrower; bigger
D) narrower; smaller

Question

Quizplus · Accepted Answer

A 95% confidence interval is wider than a 90% confidence interval because it provides more certainty that the interval contains the true population mean. Consequently, the probability of making an error (not capturing the true mean) is smaller with a 95% confidence interval.

A 90% Confidence Interval Is Constructed for the Population Mean