the fair isaac corporation (fico) score is used by credit agencies such as banks to determine whether to lend money and the interest rate to charge. Its value ranges from 300 to 850 and if you have a score over 700, you are considered to be a quality credit risk. The mean credit score of average income earners in california is estimated by Fair Isaac to be 618. a recent survey of 27 high income earners in california in california had a mean FICO score of 606 and a standard deviation of 29. Use a 0.01 significance level to test the claim that the mean FICO score of high income earners in california is less than 618, the mean score of average income earners in california