The number of times a particular computer crashes follows a

The number of times a particular computer crashes follows a Poisson distribution with an average of 5.26 times per week. What is the probability the computer will crash exactly five times next week?

Solution

Note that the probability of x successes out of n trials is          
          
P(x) = u^x e^(-u) / x!          
          
where          
          
u = the mean number of successes =    5.26      
          
x = the number of successes =    5      
          
Thus, the probability is          
          
P (    5   ) =    0.174324529 [answer]