**TI89**mainRzdifmnci(Z() Prgm ClrIO Disp "1 = large, large","2 = large, finite","3 = finite, large","4 = finite, finite" Input c ClrIO If c=3 or c=4 Then Disp "1st population size" Input k Else 0k EndIf If c=2 or c=4 Then Disp "2nd population size" Input l Else 0l EndIf Disp "x sample size" Input p Disp "xbar" Input x Disp "x sample deviation" Input s Disp "y sample size" Input q Disp "ybar" Input y Disp "y sample deviation" Input t Disp "confidence level" Input r If k0 Then s*((k-p)/(k-1))s EndIf If l0 Then t*((l-q)/(l-1))t EndIf s\invNormF((r+1)/2,0,1)b b*(s^2/p+t^2/q)e ClrIO Disp "Difference, Error" Disp {round(x-y,4),"+-",round(e,4)} Disp "Confidence Interval" Disp {round(x-y-e,4),round(x-y+e,4)} EndPrgm p