Question

Let’s say I have a Stata dataset that has two variables: type and price. The type value for each observation is a number between 1 and 10.

I want to add a third value that is the average price of all variables of that type. So, for example, if the first observation had a type of 3 and a price of 10, then I’d like to add a third value that is the average price of all observations with type=3.

How can I do this in Stata?

Answer 1

There are probably a few ways to do this but this is what I’d suggest.

gen newvar = .
forvalues i = 1/10 {

  qui sum price if type == `i', meanonly
  replace newvar = r(mean) if type == `i'

}