Paul has been working for a shop selling smart phones. He was recently

promoted to the shop manager. Being a new manager, Paul decided to introduce a

new inventory control system to his shop to reduce operating cost. Answer to the

questions below.

Assume that the number of shoppers visiting his store follows Poisson distribution

with a mean of 12 a day. Out of these shoppers, 25% make actual purchase

whereas remaining 75% do not. How many cell phones should he at least keep

every day so that probability of not being able to meet daily demand does not

exceed .05?

Assume that the number of shoppers visiting his store follows Binomial

distribution with n = 20 and p = .20. How many cell phones should he at least

keep every day so that probability of not being able to meet daily demand does

not exceed .05?