If the supermarket manager (Exercise 7.77) samples n = 50

Step 1 of 2

We have given n = 50, p = 0.9, and q = 0.1.

Let Y be the proportion of customers who dislike a new policy on cashing checks.

Hence from the exercise 7.77 we have given \(\left|\frac{Y}{n}-p\right| \leq 0.15\).

We need to find \(P\left(\left|\frac{Y}{n}-p\right| \leq 0.15\right)\).

For large n > 20 and p not too near 0 or 1 (say 0.05 < p < 0.95) the distribution approximately follows the normal distribution.