Explore BrainMass

Statistics: Standard Error and Sampling Size

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.

Number of contacts: X
14, 12, 20, 16, 46

Sales($thousands): Y
24, 14, 28, 30, 80

Number of contacts: X
23, 48, 50, 55, 50

Sales (Thousands): Y
30, 90, 85, 120, 110

a. Determine the standard error of estimate.
b. Suppose a large sample is selected (instead of just 10). About 95 percent of the predictions regarding sales would occur between what two values?

Solution Summary

This solution calculates the regression equation, estimated sales, standard error of estimate, and 95% of predictions regarding sales in a stepwise explanation. All formulas used are included.