*! version 1.2.0   13 September 1993   RG       STB-17: sg21
program define equimi
    version 3.1
* enter control group first: n mean sd n mean sd[, delta() sdelta2() Random]
    local options "Delta(string) SDelta(string) Random"
    parse "`*'", parse(" ,")
    local n1 `1'
    local u1 `2'
    local sd1 `3'
    cap confirm number `5'
    if _rc!=0 {
         local u2 `4'
         mac shift 4
         parse "`*'"
         if "`random'"!="" {
              di in red "random not allowed in this situation"
              exit 198
         }
         if "`delta'"=="" { local d1=.2*`u1' }
         else if "`delta'"!="" {
              if substr("`delta'",-1,.)=="%" {
                   local leng=length("`delta'")
                   local dp=real(substr("`delta'",1,`leng'-1))/100
                   local d1=`dp'*`u1'
              }
              else { local d1=real("`delta'") }
         }
         if "`sdelta'"=="" { local d2 `d1' }
         else if substr("`sdelta'",-1,.)=="%" {
              local leng2=length("`sdelta'")
              local dp2=real(substr("`sdelta'",1,`leng2'-1))/100
              local d2=`dp2'*`u1'
         }
         else { local d2=real("`sdelta'") }
         local se1=`sd1'/sqrt(`n1')
         local t1= ((`u1' - `u2') - (-`d1'))/ `se1'
         local t2= ((`u1' - `u2') - `d2')/ `se1'
         local CI1 = (`u1')-(invnorm(.95)*`se1')
         local CI2 = (`u1')+(invnorm(.95)*`se1')
         qui cii `n1' `u1' `sd1', level(90)
         local CI1a=$S_5
         local CI2a=$S_6
         di "Westlake version of test of Equivalence w/delta fixed and known:"
         di "   test1: "%9.3f `t1' _skip(3) "normal p-value: "%6.4f /*
              */ round(1-normprob(abs(`t1')),.0001) _skip(3) "t p-value: "%6.4f /*
              */ round(tprob(`n1'-1,`t1'),.0001)
         di "   test2: "%9.3f `t2' _skip(3) "normal p-value: "%6.4f /*
              */ round(1-normprob(abs(`t2')),.0001) _skip(3) "t p-value: "%6.4f /*
              */ round(tprob(`n1'-1,`t2'),.0001)
         di "  Confidence Interval: Lower Limit"%14.3f `CI1' _skip(2) /*
              */ "Upper Limit "%9.3f `CI2'
         di "t-Confidence Interval: Lower Limit"%14.3f `CI1a' _skip(2) /*
              */ "Upper Limit "%9.3f `CI2a'
di "Equivalence Criteria (-/+ (s)delta)"%13.3f `u2'-`d1' _skip(14) %9.3f `u2'+`d2'
         di ""
         di "t-test:"
         ttesti `n1' `u1' `sd1' `u2'
         di ""
         di "standard confidence interval:"
         cii `n1' `u1' `sd1'
         exit
    }
    local n2 `4'
    local u2 `5'
    local sd2 `6'
    mac shift 6
    parse "`*'"
    if "`delta'"=="" { local d1=.2*`u1' }
    else if "`delta'"!="" {
         if substr("`delta'",-1,.)=="%" {
              local leng=length("`delta'")
              local dp=real(substr("`delta'",1,`leng'-1))/100
              local d1=`dp'*`u1'
         }
         else { local d1=real("`delta'") }
    }
    if "`sdelta'"=="" { local d2 `d1' }
    else if substr("`sdelta'",-1,.)=="%" {
         local leng2=length("`sdelta'")
         local dp2=real(substr("`sdelta'",1,`leng2'-1))/100
         local d2=`dp2'*`u1'
    }
    else { local d2=real("`sdelta'") }
    if "`random'"=="" {
    local se1 =  (sqrt(((((`n1' - 1) * `sd1'^2) + /*
         */ ((`n2' - 1) * `sd2'^2)) / (`n1' + `n2' - 2)) * ((1/`n1')+(1/`n2'))))
    local t1= ((`u1' - `u2') - (-`d1'))/ `se1'
    local t2= ((`u1' - `u2') - `d2')/ `se1'
    local CI1 = (`u1' - `u2')-(invnorm(.95)*`se1')
    local CI1a = (`u1' - `u2')-(invt(`n1'+`n2'-2,.95)*`se1')
    local CI2 = (`u1' - `u2')+(invnorm(.95)*`se1')
    local CI2a = (`u1' - `u2')+(invt(`n1'+`n2'-2,.95)*`se1')
    di "Westlake version of test of Equivalence w/delta fixed and known:"
    di "   test1: "%9.3f `t1' _skip(3) "normal p-value: "%6.4f /*
         */ round(1-normprob(abs(`t1')),.0001) _skip(3) "t p-value: "%6.4f /*
         */ round(tprob(`n1'+`n2'-2,`t1'),.0001)
    di "   test2: "%9.3f `t2' _skip(3) "normal p-value: "%6.4f /*
         */ round(1-normprob(abs(`t2')),.0001) _skip(3) "t p-value: "%6.4f /*
         */ round(tprob(`n1'+`n2'-2,`t2'),.0001)
    di "  Confidence Interval: Lower Limit"%14.3f `CI1' _skip(2) /*
         */ "Upper Limit "%9.3f `CI2'
    di "t-Confidence Interval: Lower Limit"%14.3f `CI1a' _skip(2) /*
         */ "Upper Limit "%9.3f `CI2a'
  }
  else if "`random'"!="" {
    local pct=`d1'/`u1'
    local se3 =  (((sqrt(((((`n1' - 1) * `sd1'^2) + /*
         */ ((`n2' - 1) * `sd2'^2)) / (`n1' + `n2' - 2)))) * /*
         */ (sqrt((((1 + `pct')^2)/`n1') + (1/`n2')))))
    local t3 = ((`u1' - `u2') - (-`d1'))/ `se3'
    local t4 = ((`u1' - `u2') - (`d2'))/ `se3'
    local CI3 = (`u1' - `u2')-(invnorm(.95)*`se3')
    local CI3a = (`u1' - `u2')-(invt(`n1'+`n2'-2,.95)*`se3')
    local CI4 = (`u1' - `u2')+(invnorm(.95)*`se3')
    local CI4a = (`u1' - `u2')+(invt(`n1'+`n2'-2,.95)*`se3')
    di "Westlake version of test of Equivalence w/delta random and unknown:"
    di "   test3: "%9.3f `t3' _skip(3) "normal p-value: "%6.4f /*
         */ round(1-normprob(abs(`t3')),.0001) _skip(3) "t p-value: "%6.4f /*
         */ round(tprob(`n1'+`n2'-2,`t3'),.0001)
    di "   test4: "%9.3f `t4' _skip(3) "normal p-value: "%6.4f /*
         */ round(1-normprob(abs(`t4')),.0001) _skip(3) "t p-value: "%6.4f /*
         */ round(tprob(`n1'+`n2'-2,`t4'),.0001)
    di "  Confidence Interval: Lower Limit"%14.3f `CI3' _skip(2) /*
         */ "Upper Limit "%9.3f `CI4'
    di "t-Confidence Interval: Lower Limit"%14.3f `CI3a' _skip(2) /*
         */ "Upper Limit "%9.3f `CI4a'
  }
di "Equivalence Interval (-/+ (s)delta)" %13.3f -`d1' _skip(14) %9.3f `d2'
    di ""
    di "t-test"
    ttesti `n1' `u1' `sd1' `n2' `u2' `sd2'
    local sdt=sqrt((((`n1'-1)*`sd1'^2)+((`n2'-1)*`sd2'^2))/(`n1'+`n2'-2))
    local CIt1=(`u1'-`u2')+(invt(`n1'+`n2'-2,.05)*`sdt'*sqrt((1/`n1')+(1/`n2')))
    local CIt2=(`u1'-`u2')+(invt(`n1'+`n2'-2,.95)*`sdt'*sqrt((1/`n1')+(1/`n2')))
    di ""
    di "confidence interval: Lower Limit "%13.3f `CIt1' _skip(2) /*
         */ "Upper Limit "%13.3f `CIt2'
    di ""
    local T=(`u1'-`u2'-((`d1'+`d2')/2))/(`sdt'*sqrt((1/`n1')+(1/`n2')))
    local DEL=((`d2'-`d1')/2)/(`sdt'*sqrt((1/`n1')+(1/`n2')))
    if (abs(`T')-`DEL')<0 {
         local T1=.5*tprob(`n1'-1,abs(`T')-`DEL')
    }
    else {
         local T1=1-(.5*tprob(`n1'-1,abs(`T')-`DEL'))
    }
    if (-(abs(`T'))-`DEL')<0 {
         local T2=.5*tprob(`n2'-1,(-(abs(`T')))-`DEL')
    }
    else {
         local T2=1-(.5*tprob(`n2'-1,(-(abs(`T')))-`DEL'))
    }
    local PV=`T1'-`T2'
    di "H-A p-value: "%7.4f `PV'
end