Learn R

tapply() function

> tapply(TOTINC, SEX, mean)  # finds the mean of Total_Income based on sex

Note: 1= male, 2=female

aggregate() function

Aggregate is similar to tapply, but it is much more flexible. The general structure of aggregate is as follows::

To use aggregate()function in R, make sure to load the stats package:

> library(stats)

The following runs aggregate() with the same parameters as tapply() in previous example:

To subset the data on more than one variable such as "sex" and "pr":