Question

A manager at a company that manufactures phones has noticed that the number of faulty phones in a production run of cell phones is usually small and that. the quality of one days run seems to have no bearing on the next day.
1. if the mean number of faulty cell phones is 3.9 per day, what is the probability that no faulty phones will be produced tomorrow?

2. if the mean number of faulty cell phones is 3.9 per day, what is the probability that 3 or more faulty phones were produced in today's run?

Answer 1

It is known that number of faulty phones manufactured per day follows a Poisson distribution.
Let X be the corrosponding random variable denoting the number of faulty phones manufactured per day.
It is given that,

The p.m.f. is given by:

1. Since, the quality of one days run seems to have no bearing on the next day, here, we are to find:
   
   
   
   
   
2. Here, we are to find:
   
   
   
   
   
   
   

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