1) To evaluate if auditors might be helped in determining the chances of fraud if they carefully measure cash flow, samples of midlevel auditors from CPA firms were asked to indicate the chance of material fraud on a scale from 0 to 100 for a case. A random sample of 36 auditors used the cash-flow information. Their mean assessment was 37.46, and the sample standard deviation was 21.62. For an independent random sample of 36 auditors not using the cash-flow information, the sample mean and standard deviation were, respectively, 55.42 and 25.98. Assuming that the two population distributions are normal with equal variances, test against a two-sided alternative the null hypothesis that the population means are equal. (Use

=0.10.)

a) Let x be the mean assessment for auditors who measured cash flow and y be the mean assessment for auditors not using the cash-flow information. Determine the null and alternative hypotheses.

b) The test statistic is t=_____?

(Round to three decimal places as needed.)

c)The critical value(s) is(are)_____?

(Round to three decimal places as needed. Use a comma to separate answers as needed.)

d) There is (insufficient/sufficient) evidence of a difference in the two population means.

2) A regression equation is given below. Y=98+8X

a. What is the change in Y when X changes by +6?

b. What is the change in Y when X changes by 2?

c. What is the predicted value of Y when X=14?

d. What is the predicted value of Y when X=24?

e. Does this equation prove that a change in X causes a change in Y?