# Re: st: how to express the mean of a variable in a calculation?

 From jjc.li@utoronto.ca To statalist@hsphsun2.harvard.edu Subject Re: st: how to express the mean of a variable in a calculation? Date Tue, 07 Jul 2009 22:53:15 -0400

```Hi,

I know I forgot `' in the calculation.

Crystal

Quoting Joseph McDonnell <jockmcdock@gmail.com>:

```
```quietly summarize x2 if year>=1 & year<=5
display r(mean)
local x2mean1_5=r(mean)
di `x2mean1_5'

you can then use x2mean1_5 in your calculations. You can, in
principle, use r(mean) but this will be wiped on the next r-class
command.

If you want the mean for each individual year, you could use a loop

forvalues yr=1(1)5 {
quietly summarize x2 if year==`yr'
local mean`yr'=r(mean)
}

di `mean1'
di `mean5'

Cheers

Joseph

2009/7/8  <jjc.li@utoronto.ca>:
```
```Dear all,

I am going to calculate sth after the the regression. I know _b[x1]
represents the coef. of variable x1. But how to express the mean of variable
x2, in particular just the mean of x2 from year 1 to year 5 (let's say there
are total 10 years)?

Thanks!

Crystal

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```
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