Question

A film distribution manager calculates that 4% of the films released are flops. If the manager is correct, what is the probability that the proportion of flops in a sample of 667 released films would be greater than 5%

Answer 1

9.34%

Explanation:

p = 4%, or 0.04

n = Sample size = 667

u = Expected value = n * p = 667 * 0.04 = 26.68

SD = Standard deviation =
`√(np(1-p)) =√(667*0.04*(1-0.04))` = 5.06

Now, the question is if the manager is correct, what is the probability that the proportion of flops in a sample of 667 released films would be greater than 5%?

This statement implies that the p-vlaue of Z when X = 5% * 667 = 33.35

Since,

Z = (X - u) / SD

We have;

Z = (33.35 - 26.68) / 5.06

Z = 1.32

From the Z-table, the p-value of 1.32 is 0.9066

1 - 0.9066 = 0.0934, or 9.34%

Therefore, the probability that the proportion of flops in a sample of 667 released films would be greater than 5% is 9.34%.