To Estimate with 95% Confidence the Average Number of Kilometres

Multiple Choice

To estimate with 95% confidence the average number of kilometres that students living off-campus commute to classes every day, a random sample of 20 students was taken and produced a mean equal to 5.2 km and a standard deviation of 3.05 km. In this case, what would be the approximate value of the upper limit for a 95% confidence interval estimate for the true population mean?

A) 6.63
B) 5.20
C) 3.22
D) 2.15