This question is not an easy one, and requires putting together material in Chapters 3, 4, and 5.

Suppose we make up a driving test that we have good reason to believe should be passed by 60% of all drivers. We administer it to 30 drivers, and 22 pass it. Is the result sufficiently large to cause us to reject H0 (p 5 .60)? This problem is too unwieldy to be approached by solving the binomial for X 5 22, 23, . . . , 30. But you do know the mean and variance of the binomial, and something about its shape. With the aid of a diagram of what the distribution would look like, you should be able to solve the problem.