A cell phone manufacturer samples cell phones from the assembly to test. She noticed that the number of faulty cell phones in a production run is usually small and that the quality of one day’s run seems to have no bearing on the next day.

a) What model might you use to model the number of faulty cell phones produced in one day?

(write a name of this probability model)


An analysts estimates the mean number of defective cell phones to be 2 per day.

b) What is the probability of having a day with no faulty cell phone in a production run?
(write to 3 decimal places)

c) What is the probability of having a day with more then 3 faulty cell phones in a production run?

probability: