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 Post subject: Fisher F test code and algorithm?
PostPosted: Mon Jul 18, 2016 12:11 pm 

Joined: Mon Jul 18, 2016 11:25 am
Posts: 1
I have questions regarding this part of the code in the file variancetests.c
for Fisher's F-test:
This is the final part of the code for the test itself.

df1 = n-1;
df2 = m-1;
stat = ae_minreal(xvar/yvar, yvar/xvar, _state);
*bothtails = 1-(fdistribution(df1, df2, 1/stat, _state)-fdistribution(df1, df2, stat, _state));
*lefttail = fdistribution(df1, df2, xvar/yvar, _state);
*righttail = 1-(*lefttail);

Could you please give insights on the following points:
1) in *lefttail = fdistribution(df1, df2, xvar/yvar, _state);
shouldn't xvar/yvar be replaced by stat?
2) I am not much literate in C, but I could not find "ae_minreal" as a function (I googled and searched the source files), I suppose that it is a function that discriminate which of both inputs is the greatest. Am I right?
3) I don't really understand the bothtail formula. Shouldn't it be lefttail-righttail? (hence 2*leftail-1)?

Thanks by advance

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