In the following problem, check that it is appropriate to use the normal approximation to the binomial. Then use the normal distribution to estimate the requested probabilities. More than a decade ago, high levels of lead in the blood put 86% of children at risk. A concerted effort was made to remove lead from the environment. Now, suppose only 10% of children in the United States are at risk of high blood-lead levels.

(a) In a random sample of 180 children taken more than a decade ago, what is the probability that 50 or more had high blood-lead levels? (Round your answer to three decimal places.)

(b) In a random sample of 180 children taken now, what is the probability that 50 or more have high blood-lead levels? (Round your answer to three decimal places.)