thank you for ya help, if i cannot use if r statement there, what other code do i need to use ??? ( for some reasons it didnt show all my codes ,weird. DO you have an email ?? cus it will be better if i send my code to ya email . Thank > if r greater or equal to alphahat[k] then n1[k]:=n1[k-1]+1; > elif r greater alphahat[k] or r less than or equal (alphahat[k]+betahat[k]) then n1[k]:=n1[k-1]-1; > elif r greater (alphahat[k]+betahat[k]) or r less than or equal (alphahat[k]+betahat[k]+gammahat[k]) then n2[k]:=n2[k-1]+1; > else n2[k]:=n2[k-1]-1; > end if: