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) 312
B) 1620
C) 60
D) 540
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 $9 \times 180 = 1620$.

We Have Calculated a Confidence Interval Based on a Sample n=180.n = 180 .n=180.

We Have Calculated a Confidence Interval Based on a Sample $n = 180 .$