Mr. James McWhinney, president of Daniel-James Financial Services, believes there is a relationship between the number of client contacts and the dollar amount of sales. To document this assertion, Mr. McWhinney gathered the following sample information. The x column indicates the number of client contacts last month and the y column shows the value of sales ($ thousands) last month for each client sampled. (Round your answers to 3 decimal places.) Number of Contacts, xSales ($ thousands), yNumber of Contacts, xSales ($ thousands), y 14 24 23 30 12 14 48 90 20 28 50 85 16 30 55 120 46 80 50 110 a. Determine the 95% confidence interval, in thousands of dollars, for the mean of all sales personnel who make 40 contacts.