Question

1. UsePoissonsheet to answer this question.

Suppose that X, the number of customers arriving each hour at the only checkout counter in a local pharmacy, is approximately Poisson distributed with mean = 20 customers per hour. Find the probability that Xis more than 24. Round your answer to 4 decimal places. Put a box around your answer.  

Answer 1

$\lambda$ = 20 customer per hour

P(x>24) = 1- P(<=24)

P(x>24) = 1 - Sum of Probabilities for x = 0 to 24)

Now we will use the poisson distribution table for lambda = 20.

Below is the the required probabilities -

P(x<=24) = 0+0+0+0+0+0.0001+0.0002+0.0005+0.0013+0.0029+0.0058+0.0106+0.0176+0.0271+0.0387+0.0516+0.0646+0.0760+0.0844+0.0888+0.0888+0.0846+0.0769+0.0669+0.0557

P(x<=24) = 0.8431

P(x>24) = 1 - P(x<=24)

P(x>24) = 1 - 0.8431

P(x>24) = 0.1569