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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?  


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