*! 1.0.0  30 August 1993  RG            sg40: STB-26
program define johnson
    version 3.0
    mac def S_7                     /* will be Johnson's t1    */
    mac def S_8                     /* will be Chen's t2 */
    local exp "req noprefix"
    local if "opt"
    local in "opt"
    local varlist "req ex max(1)"
    parse "`*'"
    tempvar diff
    capture confirm number `exp'
    if _rc!=0 {
         gen `diff'=`varlist' - `exp' `if' `in'
         local varlist "`diff'"
         local exp 0
    }
    quietly sum `varlist' `if' `in'
    local n = _result(1)
    local u = _result(3)
    local s = sqrt(_result(4))
    if `s'==. { error 2001 }
    ttesti `n' `u' `s' `exp', xname(`varlist')
    qui su `varlist' `if' `in', d
#del ;
*    mac def S_7 =  $S_6 +
*         ((_result(14) * (_result(4)^(3/2))) /
*              (6 * (_result(4)^(3/2)) * sqrt(_result(1)))) +
*         (((_result(14) * (_result(4)^(3/2))) / (3 * (_result(4)^(5/2)))) *
*         sqrt(_result(1)) * (_result(3) - `exp')^2) ;
local b1 ((_result(4))*(((_result(1)-1)/_result(1))))/_result(4)^(3/2) ;
    mac def S_7 = $S_6 + `b1'/(6*sqrt(_result(1))) +
         ((2*`b1')/(6*sqrt(_result(1))))*
         (((sqrt(_result(1))*(_result(3)-`exp'))/sqrt(_result(4)))^2) ;
    di _n in gr _col(12) "Ho:  mean = " in ye "`exp'" _n
         in gr _col(20) "t1 = " in ye %3.2f $S_7
         in gr " with " in ye "$S_5" in gr " d.f." _n
         in gr _col(13) "Pr > |t| = "
         in ye %5.4f tprob($S_5,$S_7) ;
    mac def S_8 = $S_7 + ((`b1'^2)/(9*_result(1))) *
         ((((sqrt(_result(1))*(_result(3)-`exp'))/sqrt(_result(4)))) +
         (2*((sqrt(_result(1))*(_result(3)-`exp'))/sqrt(_result(4)))^2)) ;
    di _n in gr _col(12) "Ho:  mean = " in ye "`exp'" _n
         in gr _col(20) "t2 = " in ye %3.2f $S_8
         in gr " with " in ye "$S_5" in gr " d.f." _n
         in gr _col(13) "Pr > |t| = "
         in ye %5.4f tprob($S_5,$S_8) ;
#del cr
end