Hi Kris,
 
 You just need to understand the mathematics of the incomplete gamma function and the various relationships it has. The answers from both Mathematica and R are correct, except that they are giving you different estimated quantities. It depends on the way the gamma function is written. For instance in R to get the equivalent result from mathematica you should do the following
 
 answer <- gamma(9) - Igamma(9,11.1). This will give you the incomplete gamma for (9,11.1) as given by Mathematica. 
 
 You can read more about the model and am sure you will figure it out.
 
 Regards
 
 Anup


       
---------------------------------
Got a little couch potato? 
Check out fun summer activities for kids.
	[[alternative HTML version deleted]]

