I'm trying to reverse engineer a Stata program into SAS, and I'm having trouble with the gammap
function in Stata and what it correlates to in SAS. From Stata documentation, it appears that the gammap
function returns the cumulative gamma distribution.
Test Data:
PSCORE PALPHA PBETA
0.032352097 21.4639 0.002864125
0.030794526 21.4639 0.002864125
0.032952468 21.4639 0.002864125
0.041141297 21.4639 0.002864125
0.033376449 21.4639 0.002864125
0.032352097 5.7865 0.005516187
0.030794526 5.7865 0.005516187
0.032952468 5.7865 0.005516187
0.041141297 5.7865 0.005516187
0.033376449 5.7865 0.005516187
So in the Stata program, I have:
RESULT = gammap(PALPHA,PSCORE/PBETA)
I translated this in SAS as part of the CDF
function:
RESULT = CDF('GAMMA',PALPHA,PSCORE/PBETA);
However, the results are not matching up so my theory is wrong.
Stata:
0.0045025
0.0025791
0.0055082
0.0474779
0.0063245
0.5680494
0.5214182
0.5854155
0.7804033
0.5974566
SAS:
0.99394
0.99605
0.99291
0.95694
0.99209
0.54212
0.58959
0.52384
0.29454
0.51097
Could someone offer insight on what the correct correlating SAS code might be and where I'm going wrong in using the CDF
function? Should I not use the CDF
function?