It’s often useful to compare histograms for some key variable, stratified by levels of some other variable. There are several ways to display something like this. The simplest may be to plot the two histograms in separate panels.

**SAS**

In SAS, the most direct and generalizable approach is through the `sgpanel` procedure.

proc sgpanel data = 'c:\book\help.sas7bdat';

panelby female;

histogram cesd;

run;

The results are shown above.

**R**

In R, the `lattice` package provides a similarly direct approach.

ds = read.csv("http://www.math.smith.edu/r/data/help.csv")

ds$gender = ifelse(ds$female==1, "female", "male")

library(lattice)

histogram(~ cesd | gender, data=ds)

The results are shown below.

*Related*

To

**leave a comment** for the author, please follow the link and comment on their blog:

** SAS and R**.

R-bloggers.com offers

**daily e-mail updates** about

R news and

tutorials on topics such as:

Data science,

Big Data, R jobs, visualization (

ggplot2,

Boxplots,

maps,

animation), programming (

RStudio,

Sweave,

LaTeX,

SQL,

Eclipse,

git,

hadoop,

Web Scraping) statistics (

regression,

PCA,

time series,

trading) and more...

If you got this far, why not

__subscribe for updates__ from the site? Choose your flavor:

e-mail,

twitter,

RSS, or

facebook...

**Tags:** histogram, ifelse, lattice library, panelby statement, proc sgpanel, side by side histograms