Separate a variable in groups and apply some tests

[Marcel Cabral]

Hi everyone.

I´m trying to run some tests over a dataset, but I have doubts about how to separate the data in some groups.

For example, I have two variables one called "perc" and other called "at".

I want to apply a t-test to compare the means of the "perc" between the group that have values of "at" below the median of all and with the other group that have the values of "at" above the median of all.

How can I do this?

Sicerely,

Marcel.

[Ken Chui]

There are probably many ways. Here is one possibility:

sysuse auto, clear

* Gather the median
summarize mpg, detail

* Create the indicator
generate above_med = mpg >= 20 & !missing(mpg)

* t-test
ttest price, by(above_med)