We Intend to Estimate the Average Driving Time of a Group

Multiple Choice

We intend to estimate the average driving time of a group of commuters. From a previous study, we believe that the average time is 42 minutes with a standard deviation of 12 minutes. We want our 98 percent confidence interval to have a margin of error of no more than plus or minus 3 minutes. What is the smallest sample size that we should consider?

A) 87
B) 10
C) 8
D) 261