| 
 
 
| Question 1000130:  Please help me solve this problem
 Suppose the number of mechanical failures occurring in an industrial plant follows a Poisson distribution with an average of 1.4 failures per week.
 (a) What is the probability of no mechanical failures in a given week?
 (b) What is the probability that four or more mechanical failures will occur during a three-week period?
 Thanks
 Answer by Boreal(15235)
      (Show Source): 
You can put this solution on YOUR website! For (a) f(x)=exp^(-1.4)1.4^0/0! that is equal to exp(-1.4)=0.2466. That is the probability of no mechanical failures in a given week.
 For four or more, I need 1,2,3
 exp(-1.4)1.4/1=0.3452
 exp(-1.4)(1.4)^2/2=0.2417
 for 3 exp(-1.4)1.4^3/6=0.1128
 These four sum to 0.9463.
 The probability of more than 4 is 1-0.9463=0.0537
 exp(-lambda)lambda^x/x!, where lambda is the average of failures or whatever is being counted.
 | 
  
 | 
 |