Suppose that 90%, 95%, 98%, and 99% confidence intervals are computed (using the same sample) for a population proportion. Which confidence level will give the narrowest interval?
A) 99%
B) 98%
C) 95%
D) 90%

Question

Quizplus · Accepted Answer

The narrowest confidence interval is associated with the lowest confidence level because a lower confidence level means we are accepting a higher chance of error, thus requiring a smaller range to claim with that level of confidence. In this case, a 90% confidence interval will be narrower than 95%, 98%, or 99% confidence intervals.

Suppose That 90%, 95%, 98%, and 99% Confidence Intervals Are