The number of people that enter a drugstore in a given hour is a poisson random variable with parameter λ = 10. compute the conditional prob- ability that at most 3 men entered the drugstore, given that 10 women entered in that hour. what assumptions have you made?

The probability is 0.2650

Step-by-step explanation:

Let's start assuming that men and women come in at the same rate.

Let's define the following random variables :

X : ''Number of people that enter a drugstore''

M : ''Number of men that enter a drugstore''

W : ''Number of women that enter a drugstore''

The number of people will be the number of men plus the number of women

⇒

X = M + W

We are also assuming that M and W are independent random variables.

X ~ Po (10)

M ~ Po (λ1)

W ~ Po (λ2)

λ1 = λ2 because we assumed that men and women come in at the same rate.

λ1 = λ2 = λ

λ1 + λ2 = λ + λ ⇒ 2λ = 10 ⇒ λ = 5

M ~ Po (5)

W ~ Po (5)

Because X is the sum of two independent Poisson random variables.

We are looking for :

Because we assume independence.

because is a Poisson random variable with λ = 5