Last year the average daily change in the Dow Jones Industrial Index was 7.3 points. A random sample of 15 trading days this year showed the average...

Last year the average daily change in the Dow Jones Industrial Index was 7.3 points. A random sample of 15 trading days this year showed the average change to be 5.2 points with a standard deviation of 10.2. Test the claim that the average change in the index is less this year than it was last year. Use a 5% significance level.