Adding error bars to bar graph

[Frederick Asare]

Hi all, can someone please assist me with how to add error bars to the bar graph attached. Thanks.

[Nick Cox]

There is no code here or example data but it is possible to guess that your command was something like

graph bar response_time, over(younger) over(blur) asyvars

This graph is fine for showing means, but a dead end for also showing error bars. You need to switch to graph twoway.

I will illustrate my recommendation using a different dataset.

webuse nlswork, clear

keep if ind_code == 8 

statsby, by(collgrad south) clear : ci means ln_wage 

gen x1 = south - 0.1
gen x2 = south + 0.1

twoway rcap ub lb x1 if collgrad == 0, lcolor(orange) || ///
       rcap ub lb x2 if collgrad == 1, lcolor(blue)   || ///
     scatter mean x1 if collgrad == 0, ms(O) mc(orange)     || ///
     scatter mean x2 if collgrad == 1, ms(T) mc(blue)          ///
     ytitle(ln_wage) xla(0 "North" 1 "South")            ///
     legend(order(3 "not graduate" 4 "graduate")) aspect(1) xsc(r(-0.2 1.2))

See e.g. https://biostat.app.vumc.org/wiki/pu...de/Poster3.pdf and https://simplystatistics.org/posts/2...lots-must-die/ as two of many sample arguments against the bar +/- error bar dynamite, detonator or plunger plots.

See also https://www.stata-journal.com/articl...article=gr0045 (bearing in mind that the syntax of ci has changed slightly since that paper was published).

[Frederick Asare]

Thanks so much Nick. I'm very grateful for your help