*! version 1.0.0 PJG 7/15/92   (STB-9: sg10)
program define confx
version 3.0

if "`4'"=="" { 
     di in red "syntax is confx depvar indepvar yobsvar #"
     exit 198
}
     quietly sum `1'
     gen ybar=_result(3)
     quietly reg `1' `2'
     gen b1=_b[`2']
     gen syx=_result(9)  
     gen xhat=(`3'-ybar)/b1
     quietly sum `2'
     gen Xbar=_result(3)
     gen Xest=xhat+_result(3)
     gen n=_result(1)
     gen ssx=_result(4)*(n-1)
     gen t=invt((n-2),`4'/100)
     gen csq=(1/ssx)*(t*syx/b1)^2
	gen/* 
*/ cl1=Xbar+(xhat-(t*syx/b1)*sqrt(((n+1)/n)*(1-csq)+xhat*xhat/ssx))/(1-csq)
	gen/*
*/ cl2=Xbar+(xhat+(t*syx/b1)*sqrt(((n+1)/n)*(1-csq)+xhat*xhat/ssx))/(1-csq)

 if cl1<cl2 { ren cl1 Llim
		ren cl2 Ulim 
}

 else if cl1>cl2 { ren cl1 Ulim 
			ren cl2 Llim	 
}

    keep `1' `2' `3' Xest Llim  Ulim
     la var `1'"Standard y-values, depvar"
     la var `2'"Standard x-values, indepvar"
     la var `3'"Experimental y obs.; unknown x"
     la var Xest"Estimated x values"
     format Xest %8.2f
     format Ulim %8.2f
     format Llim %8.2f
     list
end