# Math Help - integration of pdf of gamma distribution

1. ## integration of pdf of gamma distribution

the pdf of gamma distribution is [e^(-y/a)*(y/a)^(n-1)] / (a*(n-1)!)
I'm trying to find P(Y>5) by integration the pdf from 5 to Infinity but it doesn't work out well...

2. Originally Posted by godai
the pdf of gamma distribution is [e^(-y/a)*(y/a)^(n-1)] / (a*(n-1)!)
I'm trying to find P(Y>5) by integration the pdf from 5 to Infinity but it doesn't work out well...
See the cdf given here Gamma distribution - Wikipedia, the free encyclopedia for why you're probably having trouble ....