Data on the numbers of hospital admissions resulting from motor vehicle crashes are given below for Fridays on the 6th of a month and Fridays on the following 13th of the same month. Assume that the paired sample data is a simple random sample and that the differences have a distribution that is approximately normal. Construct a95% confidence interval estimate of the mean of the population of differences between hospital admissions. Use the confidence interval to test the claim that when the 13th day of a month falls on aFriday, the numbers of hospital admissions from motor vehicle crashes are not affected.

Friday the 6th 6 11 2 7 4

Friday the 13th 12 12 11 15 15