find the indicated probabilities using the geometric distrib

find the indicated probabilities using the geometric distribution or poisson distribution. Then determine if the events are unusual. If convenient, ust a Poisson probability table or technology to find the probabilities. Assume the porbability that you will make a sale on any given telephone call is 0.24. Find the probability taht you (a) make your first sale on the fifth call, (b) make your sale on the first, second,or third call, and (c) do not make a sale on the first three calls.

Solution

P(X=x)=(1.2^x)*exp(-1.2)/x! for x=0,1,2,...

So the probability is

P(X=5) =(1.2^5)*exp(-1.2)/5!=0.006245563