# Summarize statistics by Groups in R & R Commander

**eKonometrics**, and kindly contributed to R-bloggers]. (You can report issue about the content on this page here)

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R is great at accomplishing complex tasks. Doing simple things with R though takes some effort. Consider the simple task of producing summary statistics for continuous variables over some factor variables. Using Stata, I’d write a brief one-liner to get the mean for one or more variables using another variable as a factor. For instance, **tabstat Horsepower RPM, by(Type)** in Stata produces the following:

The doBy package in R offers similar functionality and more. Of particular interest for those who teach R based statistics courses in the undergraduate programs is the **doBy plugin** for R Commander. The plugin was developed by **Jonathan Lee** and it is a great tool for teaching and for quick data analysis. To get the same output as the one listed above, I’d click on the **doBy plugin** to get the following dialogue box:

The dialogue box results in the following simple syntax:

**summaryBy(Horsepower+RPM~Type, data=Cars93, FUN=c(mean))**

You may first have to load the data set: **data(Cars93, package=”MASS”)**

And the results are presented below:

Jonathan has also created GUIs for order by, sample by, and split by within the same plug-in. A must use plug-in for data scientists.

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**eKonometrics**.

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