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) 60
B) 540
C) 312
D) 1620
E) 20

Question

Quizplus · Accepted Answer

To reduce the margin of error to one third, the sample size must be increased by a factor of nine (since the margin of error is inversely proportional to the square root of the sample size). Therefore, the new sample size should be 180 * 9 = 1620.

We Have Calculated a Confidence Interval Based on a Sample