MACRO

Fisher nreps n1 n2 x obsdiff

Mconstant nreps n1 n2 x x1 x2 n nx I obsdiff Pvalue Count
Mcolumn sample trmt1 diffprop phat1 phat2

Let n = n1 + n2
Let nx = n - x
Set sample
x(1)
nx(0)
End

Let Count = 0

Do I = 1:nreps
Sample n1 sample trmt1
Let x1 = sum(trmt1)
Let x2 = x - x1
Let diffprop(I) = x1/n1 - x2/n2
If abs(diffprop(I)) GE obsdiff
Let Count = Count +1
EndIf
EndDo

Let Pvalue = Count/nreps
Print Pvalue

Stem-and-Leaf diffprop.

Histogram diffprop;
  Percent;
  CutPoint -1:1/.1;
  Bar;
    Type 1;
    Color 3;
  Title "Resampling Distribution";
  Title "Difference in 2 proportions";
  Minimum 1 -1;
  Maximum 1 1;
  ScFrame;
  ScAnnotation;
  Axis 1;
    Label "Difference in Proportions";
  Axis 2;
  Tick 1;
    NMajor 5;
    NMinor 4;
  Tick 2;
    NMajor 6;
    NMinor 4.

ENDMACRO