program define fitline
version 2.1
        capture drop h_9
mac def _varlist "req ex "
mac def _if "optional"
mac def _options "*"
parse "%_*"
parse "%_varlist", parse(" ")
di " "
di "Enter an X-axis label (<20 characters),"
di "     OR press <Enter> to use " in red "   %_2  " in white " as the label."
di "X-label..." _r(xn)
di " "
if "%xn"=="" {mac def xn "%_2"}
mac def xnm "b2("%xn")"
di " "
di "Enter a Y-axis label (<20 characters),"
di "     OR press <Enter> to use " in red "   %_1  " in white "  as the label."
di "Y-label..." _r(yn)
di " "
if "%yn"=="" {mac def yn "%_1"}
macro define ynm "l1(" ") l2("%yn")"
        quietly{
           regress %_1 %_2 %_if
           predict h_9 }
          macro define a=_coef[_cons]
           macro define a =  substr(string(%a),1,6)
          macro define b=_coef[%_2]
            macro define b = substr(string(%b),1,6)
          macro define c =_result(8)
            macro define c = substr(string(%c),1,4)
   macro define d "t1("%yn = %a + %b %xn") b1("Linear Regression")"
        macro define p=fprob(_result(3),_result(5),_result(6))
 if %p<.001 { mac def p = .0001 }
          macro define p = substr(string(%p),1,4)
        macro define e "t2("Adjusted R-square= %c <[][]> p= %p")"
gr %_1 h_9 %_2 %_if, s(oi) sort c(.l) xlab ylab %e %d %xnm %ynm %_options
       if "%_options"=="" {
          display " "
   display "   To print graph, run fitline specifying a filename:"
          display "         fitline %_1 %_2, saving(jt1)"}
         drop h_9
end