A, b, c, d

18. If n is the sample size and p is the population proportion of successes, and X is the number of successes in the sample. Use the normal approximation to find the probability: a) n = 538, p = 0.86; find P( X 5 470) b) n = 99, p = 0.57; find P(X 2 55) c) n = 442, p = 0.54; find P(X ( 243) d) n = 61, p = 0.43; find P(20 s X 5 24)