Suppose that the probability p of success on any trial of a binomial distribution equals 0.90. For which of the following number of trials, n, would the normal distribution provide a good approximation to the binomial distribution?
A) 25
B) 35
C) 45
D) 55

Question

Quizplus · Accepted Answer

According to the normal approximation to the binomial distribution, the approximation is good when both np and n(1-p) are greater than or equal to 10. In this case, np= 55(0.90) = 49.5 and n(1-p) = 55(0.10) = 5.5, which means the approximation is good only for n = 55. For the other options, np and n(1-p) are less than 10, which means the normal approximation may not be accurate.

Suppose That the Probability P of Success on Any Trial