Create variable

[Maria Koutsi]

I would like to create a new variable which will be the average value of 50 countries. That is, to create panel data analysis in time series analysis. Is it econometric correct?

[Carlo Lazzaro]

Maria:
I fail to get what you're after.
That said, you may find what follows useful (two different means):

. use "https://www.stata-press.com/data/r17/nlswork.dta"
(National Longitudinal Survey of Young Women, 14-24 years old in 1968)

. bysort idcode: egen wanted_1=mean(ln_wage)

. egen wanted_2=mean(ln_wage)

. list idcode ln_wage wanted_1 wanted_2 in 1/20

     +-----------------------------------------+
     | idcode    ln_wage   wanted_1   wanted_2 |
     |-----------------------------------------|
  1. |      1   1.451214   2.040433   1.674907 |
  2. |      1    1.02862   2.040433   1.674907 |
  3. |      1   1.589977   2.040433   1.674907 |
  4. |      1   1.780273   2.040433   1.674907 |
  5. |      1   1.777012   2.040433   1.674907 |
     |-----------------------------------------|
  6. |      1   1.778681   2.040433   1.674907 |
  7. |      1   2.493976   2.040433   1.674907 |
  8. |      1   2.551715   2.040433   1.674907 |
  9. |      1   2.420261   2.040433   1.674907 |
 10. |      1   2.614172   2.040433   1.674907 |
     |-----------------------------------------|
 11. |      1   2.536374   2.040433   1.674907 |
 12. |      1   2.462927   2.040433   1.674907 |
 13. |      2   1.360348   1.688055   1.674907 |
 14. |      2   1.206198   1.688055   1.674907 |
 15. |      2   1.549883   1.688055   1.674907 |
     |-----------------------------------------|
 16. |      2   1.832581   1.688055   1.674907 |
 17. |      2   1.726721   1.688055   1.674907 |
 18. |      2    1.68991   1.688055   1.674907 |
 19. |      2   1.726964   1.688055   1.674907 |
 20. |      2   1.808289   1.688055   1.674907 |
     +-----------------------------------------+

.