In a random sample of 545 accountants engaged in preparing county operating budgets for use in planning and control, 117 indicated that estimates of cash flow were the most difficult element of the budget to derive.
a. Test at the 5% level the null hypothesis that at least 25% of all accountants find cash flow estimates the most difficult estimates to derive.
b. Based on the procedure used in part a, what is the probability that the null hypothesis would be rejected if the true percentage of those finding cash flow estimates most difficult was each of the following?
i. 20%
ii. 25%
iii. 30%