statsby mean=r(mean) max=r(max) min=r(min), by(rep78): sum mpg
twoway scatter mean rep78 || ///
rbar mean max rep78, bcolor(blue) barw(0.01) || ///
rbar mean min rep78, bcolor(blue) barw(0.01) ///
legend(off) ytitle(Miles per gallon) yla(, ang(h)) ///
note(Blue bars show range with mean)