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.
a. Determine the regression equation.
b. Determine the estimated sales if 40 contacts are made.
c. Determine the standard error of estimate.
d. Suppose a large sample is selected (instead of just 10). About 95 percent of the predictions regarding sales would occur between what two values?