As lending standards tightened after a Great Recession, there is some concern that the average credit score of a bor rower with a mortgage owned by Fannie Mae has decreased from its prior average of 771. A random sample of 30 mortgages recently revealed a credit score of 767 with a sample standard deviation of 15. Conduct a hypothesis test at significance level =.09

M9.2: Hypothesis Testing HT : 0 Unknown Step 3: Calculate the appropriate test statistic Step 4: Rejection Region/Critical Value Method . Determine the appropriate critical value(s) compare with t-test statistic to and state your decision. Step 4': p- Value Method . Calculate the p-value, compare with a, and state your decision. Step 5: State the conclusion in terms of the problem. 154