We have calculated a confidence interval based on a sample of n = 180. Now we want to get a better estimate with a margin of error only one third as large. We need a new sample with n at least…
A) 540
B) 20
C) 60
D) 1620
E) 312

Question

Quizplus · Accepted Answer

Since we want the margin of error to be only one third as large, we need to increase the sample size by a factor of 9. This means that the new sample size would be 9 times greater than the original sample size, or n = 180 x 9 = 1,620. Therefore, the best choice is D.

We Have Calculated a Confidence Interval Based on a Sample