Exit polling has been a controversial practice in recent elections, because early release of the resulting information appears to affect whether or not those who have not yet voted will do so. 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 will be selected.

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

b. What is the probability that at least 20 will 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 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.)