7.58 Suppose that 90% of all registered California voters favor banning the release of information from exit polls in presidential elections until after the polls in California close. A random sample of 25 registered California voters is to be selected.

a. What is the probability that more than 20 favor the ban?

b. What is the probability that at least 20 favor the ban?

c. What are the mean value and standard deviation of the number of voters in the sample who favor the ban?

d. If fewer than 20 voters in the sample favor the ban, is this at odds with the assertion that (at least) 90%

of California registered voters favors the ban? (Hint:

Consider P(x  20) when p  .9.)