A highway inspector needs an estimate of the mean weight of trucks crossing a bridge

on the Interstate highway system. She selects a random sample of 49 trucks and finds

a mean of 15.8 tons with a sample standard deviation of 3.85 tons. The 90 percent

confidence interval for the population mean is

A. 14.72 to 16.88 tons.

B. 14.90 to 16.70 tons.

C. 14.69 to 16.91 tons.

D. 14.88 to 16.72 tons.