A survey found that 52% of U.S. teens ages 16 to 18 have a savings account. You randomly select 45 U.S. teens ages 16 to 18 and ask them whether they have a savings account. Find the probability that the number who have a savings account is

(a) At most 15,

(b) Exactly 25, and

(c) Greater than 30, and

(d) Identify any unusual events. Explain.

Determine whether you can use a normal distribution to approximate the binomial distribution. If you can, use the normal distribution to approximate the indicated probabilities and sketch their graphs. If you cannot, explain why and use a binomial distribution to find the indicated probabilities.