Question 1190729:  The number of earthquake tremors in a 12-month period appears to be distributed as a Poison random variable with mean of 6. Assume the number of tremors from one 12-month period is independent of the number in the next 12-month period.  
a. What is the probability that there are 10 tremors in 1 year?  
b. What is the probability that there are 18 tremors in 2 year?  
c. What is the probability that there are no tremors in a 1-month period?  
d. What is the probability that there are more than 5 tremors in a 6-month period?  
 
 Answer by Boreal(15235)      (Show Source): 
You can  put this solution on YOUR website! a. This is e^(-6)*6^10/10!=0.0413 or poissonpdf (2ndVARS and scroll to poissonpdf then ENTER (6,10) for poissonpdf) 
b. this would be poisson 18, 12 or e^(-12)*12^18/18!=0.0255 
c. for 1 month use parameter 0.5, 6/12 since these are proportional to time 
look for 0 tremors so e^(-0.5)*0.5^0/0!=0.6065 
d. The parameter would be 3 for a 6 month period. 1-poissoncdf(3,5)=0.0839 
 
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