Chapter 12.2, Problem 93E

In Exercises 12.85–12.94, use Procedure 12.2 on page 557 to perform an appropriate hypothesis test. Be sure to check the conditions for using that procedure.

12.93 Washing Up. A Harris Interactive survey found that 92.0% of 1001 American adults said they always wash up after using the bathroom.

a. At the 5% significance level, do the data provide sufficient evidence to conclude that more than 9 of 10 Americans always wash up after using the bathroom?

b. Repeat part (a), using a 1% level of significance.