You are here (click or tap to change) Back to Chapter 8 Main Page
Problem 1
8.5 Small-Sample Test of Hypothesis about a Population Mean
The CEO of Equifax credit reporting agency claims the average credit rating has dropped below 675 points. A study of 20 randomly selected credit scores had an average of 660 points and a standard deviation of 95.3 points. Use a 5% significance level to test the claim that credit scores are now on average below 675 points. The CEO claims the results are not valid since they came from too small a sample. Is there any merit to his argument?
Ask the Professor