7-30. Let X be Poisson random variable with mean = 20. Approximate the following probabilities using

7-30. Let X be Poisson random variable with mean λ = 20. Approximate the following probabilities using the normal distribution:

(a) P(16 ≤ X ≤ 20)

(b) P(16 < X ≤ 20)

(c) P(16 < X < 20)