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Dear fellow forists,

although the headline might be exaggerating, the Gamma Distribution is nowadays heavily used in financial problem solving (eg. insurance) - besides its many uses in engineering & operations research.

Therefore I'm kindly asking you: Has anybody already tried to implement a Gamma Distribution with the HP17bII+ (or compatible) SOLVER routines?

I have a working solution already, but because of it's implementor (me), it's far from being a quick to enter formula - albeit working correctly, as far as I can tell (I used Gauss Integration & coefficients from Stegun).

Somebody able to reach a helping hand?


Peter A. Gebhardt

Edited: 29 July 2010, 8:28 a.m.

I remember seeing that Viktor T. Toth has a Gamma function for the 17BII on his site at:


Perhaps this can help? (Sorry, I am not very literate in statistical mathematics).

Hi, Peter;

I know that the Gamma Distribution implies some hard brainjob (see here or the Wikipedia's way), but I do not recall seeing the implementations you mention. Not an excuse of mine, at the time I was studying at the engineer's course, I did not have the inclination to go deeper in math and research tools. If I only could tell how I regret...

Can you point me to some reference? I am always digging to find information, it is easy when we know where to dig.


Luiz (Brazil)

Here's the obvious (and obligued) reference for the Gamma distribution:


Having a Gamma function takes you half way there, the rest is just achievable with a little further effort.


Luiz, Angel,

could you pls. send me your PM address, so I can enclose not only the ASCII .EQN code of my trial but also the .STA files for the 200LX (needed for the GAUSS method of integration).

Both can be used either on a native 200LX or on HPCALC under DOS.

Thanks to all of you for your kind responses!

Peter A. Gebhardt

PS: A final (hopefully optimized) solution will be provided as an article here, if we are successful ;-)

Edited: 29 July 2010, 7:29 p.m.