*! version 1.0.0   15 February 1995  STB-36 sg69
program define besd
    version 4.0
* if chi, then 1=chi^2 and 2=N
* if t, then 1=t and 2=df
* if F, then 1=F and 2=denominator df
    local options "Chi t F"
    parse "`*'", parse(" ,")
    local dist `4'
    if "`4'"=="" {
         capture {
              assert `1'>-1.0 & `1'<1.0
         }
         if _rc!=0 {
              di in red "'r' must be between -.999 and +.999"
              exit
         }
         local r=`1'
    }
    else if substr("`dist'",1,1)=="c" {
         confirm integer number `2'
         local r=sqrt(`1'/`2')
    }
    else if "`dist'"=="t" {
         confirm integer number `2'
         local r=sqrt(`1'^2/((`1'^2)+`2'))
    }
    else {
         confirm integer number `2'
         local r=sqrt(`1'/(`1'+`2'))
    }
    local diff=`r'
    local besdp=.5+(`r'/2)
    local besdn=.5-(`r'/2)
    di "Difference in 'success' rates = " %5.3f `diff'
    di "'Experimental success' rate = "%5.3f `besdp' _skip(2) "& 'control "/*
         */ "success' rate = " %5.3f `besdn'
end