A multiple-choice examination consists of 90 questions, each having possible choices a, b, c, and d. Approximate the probability that a student will get more than 19 answers correct if he randomly guesses at each answer. (Note that, if he randomly guesses at each answer, then the probability that he gets any one answer correct is 0.25.) Use the normal approximation to the binomial with a correction for continuity. Round your answer to at least three decimal places. Do not round any intermediate steps. (If necessary, consult a list of formulas.)

Suppose that 16% of the population of the U.S. is left-handed. If a random sample of 200 people from the U.S. is chosen, approximate the probability that fewer than 35 are left-handed. Use the normal approximation to the binomial with a correction for continuity. Round your answer to at least three decimal places. Do not round any intermediate steps. (If necessary, consult a list of formulas.) 0 X

Suppose that a new treatment is successful in curing a common ailment 68% of the time. If the treatment is tried on a random sample of 60 patients, approximate the probability that at most 43 will be cured. Use the normal approximation to the binomial with a correction for continuity. Round your answer to at least three decimal places. Do not round any intermediate steps. (If necessary, consult a list of formulas.) X

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