Superimposing graphs

[Mangji Zo]

Hi everyone,

I am relatively new to using Stata for graphs and I want to superimpose a normal distribution over a histogram (see below). I am not sure what the code should be for the graphs. Thank you for any advice!

[Carole J. Wilson]

See help histogram. One of the options is -normal-, allowing for the overlay of a normal density curve.

[Mangji Zo]

Hi Carole,

Thank you for the quick and helpful response! I looked up help histogram and only managed to graph this (see below). Is there any way to move the curve to the centre similar to Post #1? Thank you!

histogram zhawho_cutoff, normal

[Liu Qiang]

Hi Carole,

Thank you for the quick and helpful response! I looked up help histogram and only managed to graph this (see below). Is there any way to move the curve to the centre similar to Post #1? Thank you!

histogram zhawho_cutoff, normal

[ATTACH=CONFIG]n1458824[/ATTACH]

you may try this code:

 hist zhawho_cutoff, addplot(function y=normden(x,0,1),range(-5 5))

[Leonardo Guizzetti]

A slightly more general approach described by Liu Qiang is to bulid your graph with each plot element, one at a time. Using -||- allows you to add a new graphic element. As described above, you may plot general functions, one of which is the Normal density as provided by Stata.

Here's a working example:

sysuse bpwide
graph twoway hist bp_before || (function y = normalden(x, 120, 20), range(50 200) lw(medthick) lcol(black) ) ///
   , legend(label(1 "Blood Pressure (mm Hg)") label(2 "N(120, 20) density"))

[Mangji Zo]

Thank you so much for the codes and the advice!