Question

Suppose that 95% of all registered voters in a certain state favor banning the release of information from exit polls in presidential elections until after the polls in that state close. A random sample of 25 registered voters is to be selected. Let x = number of registered voters in this random sample who favor the ban. (Round your answers to three decimal places.)

(a)

What is the probability that more than 20 voters favor the ban?

(b)

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

(c)

What is the mean value of the number of voters who favor the ban?

What is the standard deviation of the number of voters who favor the ban?

(d)

If fewer than 20 voters in the sample favor the ban, is this inconsistent with the claim that (at least) 95% of registered voters in the state favor the ban? (Hint: Consider

P(x < 20)

when

p = 0.95.)

Since

P(x < 20) =  ,

it seems  ---Select--- plausible unlikely that less 20 voters in the sample would favor the ban when the true proportion of all registered voters in the state who favor the ban is 95%. This suggests this event would be  ---Select--- inconsistent consistent with the claim that (at least) 95%. of registered voters in the state favor the ban.

You may need to use the appropriate table in the appendix or technology to answer this question.

Answer 1