Column Mean

[Donovan Pollack]

Hello,

Sorry if this is a simple question, but I am trying to generate a variable that is an average of the rows above it (a column mean). However, its not clear to me how to do this.

Using collapse will not work because I have different groups in the first column and because stata requires a "by" variable this would not work.

There doesn't appear to be an equivalent command for column to creating means as there is for rows (i.e. rowmean)

Has anyone found a way to generate a variable like this?

thanks!

Donovan

[Nick Cox]

A running mean is just a running sum divided by a running count. This may help; if not, and other answers don't help, please give a data example as we always request (FAQ Advice #12).

sysuse auto, clear
sort mpg 
gen meansofar = sum(mpg) / sum(mpg < .) 

[Marcos Almeida]

Hazarding a wild guess (on account of the term "different groups in the first column"), I wonder whether you meant something like this:

. by foreign, sort : egen mymean = mean(mpg)