Customers arrive at a checkout counter in a department

Step 1 of 4

Let us consider a random variable ‘Y’ it presents the number of customers arrive at a checkout counter in a department store according. Here Y follows poisson distribution with parameter \(\lambda=7\).

The probability mass function of poisson distribution is given by:

\(P(Y)=\frac{e^{-\lambda} \lambda^{y}}{y !}, \mathrm{y}=0,1,2, \ldots, \mathrm{n}\)

Here our goal is:

a). We need to find the probability of no more than three customers arrive.

b). We need to find the probability of at least two customers arrive.

c). We need to find the probability of exactly five customers arrive.