I am using Excel 2007 a lot for data entry and reporting. So I was wondering about an old bug wrt the GAMMADIST function I stumbled upon when I wanted to compare my implementation of the Incomplete Gamma function with Excel. Well,
still produces #NUM!. This particular bug is known here.
There are other reports about accuracy issues with older versions of Excel, see e.g.:
There have been improvements in Excel XP/2003, but some issues remained:
- On the accuracy of statistical procedures in Microsoft Excel 2000 and Excel XP
In case you want to know the answer for the above formula, let’s use my implementation from GAMS:
1 scalar s;
2 s = gammareg(0.1/1,0.1);
3 option s:8;
4 display s;
---- 4 PARAMETER s = 0.82755176
I don’t think this is a particularly difficult point to evaluate. Nothing strange going on here. So I don’t understand why Excel has problems here.