A Highway Inspector Needs an Estimate of the Mean Weight

Multiple Choice

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.