For Exercises perform these steps.

a. State the hypotheses and identify the claim.
b. Find the critical value(s).
c. Compute the test value.
d. Make the decision.
e. Summarize the results.

Use the traditional method of hypothesis testing unless otherwise specified.

Find the 99% confidence interval for the difference in the population proportions for the data of a study in which 80% of the 150 randomly selected Republicans surveyed favored the bill for a salary increase and 60% of the200 randomly selected Democrats surveyed favored the bill for a salary increase.