topic Re: How to add error bars to a clustered vertical bar graph? in SAS Programming

How to add error bars to a clustered vertical bar graph?

mcknigh3 — Tue, 12 Oct 2021 21:00:11 GMT

Hi there,

I am having trouble adding error bars to each bar in my vertical bar chart using Proc sgplot. First of all, is this even possible? Every discussion forum/questions never shows grouped bar charts. I have all the options on in my code to enable error bars but they are not being produced on the graph. My code is below - Is there a step I am missing?

Proc sgplot data=LSMTrtTOD1;
  vbar TOD / response=Estimate stat=mean numstd=2 limitstat=stderr limits=both
   group=Trt groupdisplay=cluster fillpattern nofill;
   keylegend / position=top noborder;
  yaxis grid;
Run;

Re: How to add error bars to a clustered vertical bar graph?

ballardw — Tue, 12 Oct 2021 21:04:40 GMT

Data?

Can't test code without data.

Re: How to add error bars to a clustered vertical bar graph?

Reeza — Tue, 12 Oct 2021 21:11:52 GMT

Works fine for me - perhaps your errors are quite small? Note that not all bars have error bars, haven't investigated why but guessing it has to do with the N involved or to small to see.

Proc sgplot data=LSMTrtTOD1;
  vbar TOD / response=Estimate stat=mean numstd=2 limitstat=stderr limits=both
   group=Trt groupdisplay=cluster fillpattern nofill;
   keylegend / position=top noborder;
  yaxis grid;
Run;

@mcknigh3 wrote:

Hi there,

I am having trouble adding error bars to each bar in my vertical bar chart using Proc sgplot. First of all, is this even possible? Every discussion forum/questions never shows grouped bar charts. I have all the options on in my code to enable error bars but they are not being produced on the graph. My code is below - Is there a step I am missing?
Proc sgplot data=LSMTrtTOD1;
  vbar TOD / response=Estimate stat=mean numstd=2 limitstat=stderr limits=both
   group=Trt groupdisplay=cluster fillpattern nofill;
   keylegend / position=top noborder;
  yaxis grid;
Run;

Re: How to add error bars to a clustered vertical bar graph?

mcknigh3 — Tue, 12 Oct 2021 21:16:55 GMT

Sorry I was having trouble adding data - it's attached as a file.

Re: How to add error bars to a clustered vertical bar graph?

mcknigh3 — Tue, 12 Oct 2021 21:22:51 GMT

You can see them on the graph though? Because I can't.

Re: How to add error bars to a clustered vertical bar graph?

Reeza — Tue, 12 Oct 2021 21:33:31 GMT

If you run the exact code I posted - no changes do you see error bars?
I changed the code to reference the sashelp.cars data set and it works for me.

Re: How to add error bars to a clustered vertical bar graph?

Reeza — Tue, 12 Oct 2021 21:35:54 GMT

Ah...you're trying to reference a variable STDERR and this plot is calculating it dynamically which you are not doing.
I think you want to use VBARPARM instead where you specify the pre-calculated statistics.

Re: How to add error bars to a clustered vertical bar graph?

mcknigh3 — Tue, 12 Oct 2021 21:56:54 GMT

Thank you - this worked! Would there be a reason why the upper limit bar isn't being displayed though?

Re: How to add error bars to a clustered vertical bar graph?

Reeza — Tue, 12 Oct 2021 21:59:28 GMT

Can you share your new code?

Re: How to add error bars to a clustered vertical bar graph?

mcknigh3 — Tue, 12 Oct 2021 22:04:09 GMT

Proc sgplot data=LSMTrtTOD1 noborder;
  vbarparm category=TOD response=Estimate / limitlower=stderr limitupper=stderr
   group=Trt groupdisplay=cluster fillpattern nofill ;
  yaxis grid Label= 'Daily distance (m)';
Run;

Sorry - I am pretty well new at this!

Re: How to add error bars to a clustered vertical bar graph?

Reeza — Tue, 12 Oct 2021 22:06:42 GMT

Limit lower and upper require the actual values (ie Estimate+stderr = upper), so you need to do the math prior to this step to provide the actual values, not just the error value.

Re: How to add error bars to a clustered vertical bar graph?

mcknigh3 — Tue, 12 Oct 2021 22:28:14 GMT

Ah yes - thank you so much!