Hello there,

Please see following link attached

Best wishes

http://stats.stackexchange.com/questions/20648/how-to-test-whether-a-sample-of-data-fits-the-family-of-gamma-distribution

use the non parametric methods..

you can use QQ plot. for computing quantiles MATLAB gaminv command can be used. There are also redymade macros in SYSTAT and must be also in R.