--- Joseph Wagner <[email protected]> wrote:
> I created box plot graph with of 3 X variables over the same Y
> variable but was then asked to produce a similar graph this time
using
> mean (not median) and +/- 95% CI. I don't think Stata can do this
> but thanks to a post by Nick three years ago, I was able to (sort of)
> create these:
>
> egen mean = mean(cont), by(cat)
> egen sd = sd(cont), by(cat)
> gen upper = mean + sd
> gen lower = mean - sd
>
> scatter mean cat || rcap upper lower cat
Notice that this way you won't get a 95% confidence interval but a 68%
confidence interval (assuming you have many cases (say 100+))
> . . . is the example Nick gave but how would (or could I?) do this
> for three different X variables (in Nick's example I suppose it would
> be 3 different 'cont' variables) on the same graph? I can do
> this for two but not 3 which brings me to my next problem:
>
> The box plots I created earlier were each side by side for the same
> value of X (rather than on top of one another) but the two -rcap-
> graphs are on top of each other making it impossible to differentiate
> the two lines (three would be even worse). Is there a way to
> separate these lines or do I need to graph these data in another way
> altogether?
you can shift the axes around by adding and subtracting numbers
In addition to Nick's suggestion I reccomend
Newson R. Confidence intervals and p-values for delivery to the end
user. The Stata Journal 2003; 3(3): 245-269. You can download a
pre-publication draft from Roger's website:
http://www.imperial.ac.uk/nhli/r.newson/papers.htm
Hope this helps,
Maarten
-----------------------------------------
Maarten L. Buis
Department of Social Research Methodology
Vrije Universiteit Amsterdam
Boelelaan 1081
1081 HV Amsterdam
The Netherlands
visiting address:
Buitenveldertselaan 3 (Metropolitan), room Z434
+31 20 5986715
http://home.fsw.vu.nl/m.buis/
-----------------------------------------
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