use http://fmwww.bc.edu/repec/bocode/c/cavalry.dta, clear
hangroot deaths [fw=freq],             ///
   dist(poisson) ci                    ///
   ylab(0           "0"                ///
        `=sqrt(5)'  "5"                /// 
        5           "25"               ///
        `=sqrt(50)' "50"               /// 
        `=sqrt(75)' "75"               ///
        10          "100")             ///
   ytitle("frequency (square root scale)")