**TI89**mainRtdifmnciƒ¥Z)() Prgm ClrIO 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 Disp "pooled?" Input z If z=1 Then p+q-2n ¨(((p-1)s^2+(q-1)t^2)/n)¨(1/p+1/q)d Else int((s^2/p+t^2/q)^2/((s^2/p)^2/(p-1)+(t^2/q)^2/(q-1)))n ¨(s^2/p+t^2/q)d EndIf s\tinv((1-r)/2,n)b b*de 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 äåÜŸª