*! version 1.0.0 20 January 1994  RG            sg43: STB-28
program define modti
    version 3.1
* enter control group n, mean, sd; then treated group n, mean
    parse "`*'", parse(" ,")
    confirm integer number `1'
    confirm number `2'
    confirm number `3'
    local n1 `1'
    local u1 `2'
    local s1 `3'
    confirm integer number `4'
    confirm number `5'
    local n2 `4'
    local u2 `5'
    if `n1'<=1 { error 2001 }
    if `s1'<=0 { error 411  }
    tempvar tm
    scalar `tm'=(`u1'-`u2')/sqrt((`s1'^2)*((1/`n1')+(1/`n2')))
    di "modified t-statistic: "%7.3f `tm' _skip(5) "df: "`n1'-1
    di _skip(10) "2-sided p-value: "%6.4f tprob(`n1'-1,`tm')
    di _skip(10) "1-sided p-value: "%6.4f .5*tprob(`n1'-1,`tm')
end