Ernest Berkhout replied to Lok Wong
> >I have "area,education,gender,wage"in my dataset...Now I
> want to calculate
> >the mean and GINI coefficient of only male wage by area and
> >education...and assign these values to females in the same
> area-education
> >group..How could I do that?
>
> First, let me point out that you might learn something from
> the collection
> of FAQs on
> http://www.stata.com/support/faqs/
>
> In a quick scan, I think that this one might be of interest to you
> http://www.stata.com/support/faqs/data/weighted.html but
> ofcourse thare may
> be other as well.
>
> Apart from that, your questions sounds like the following
> approach to me:
>
> egen group=(area education)
> levels group
> foreach x of local group {
> summ wage if sex=="male" [aw=weight]
> replace wage = r(mean)
> }
In addition -- and note that Ernest's suggestion
is schematic, and not workable code -- there
is a general "copying down" technique useful
in many problems.
Lok Wong wants to calculate for _males_ and to
copy the results to _females_. An analogue of
that with the auto data is to calculate
for foreign cars, and copy to domestic.
. bysort rep78 : egen meanmpg = mean(mpg) if foreign
(52 missing values generated)
. sort rep78 meanmpg
. list rep78 meanmpg foreign
+-----------------------------+
| rep78 meanmpg foreign |
|-----------------------------|
1. | 1 . Domestic |
2. | 1 . Domestic |
3. | 2 . Domestic |
4. | 2 . Domestic |
5. | 2 . Domestic |
|-----------------------------|
6. | 2 . Domestic |
7. | 2 . Domestic |
8. | 2 . Domestic |
9. | 2 . Domestic |
10. | 2 . Domestic |
|-----------------------------|
11. | 3 23.33333 Foreign |
12. | 3 23.33333 Foreign |
13. | 3 23.33333 Foreign |
14. | 3 . Domestic |
15. | 3 . Domestic |
|-----------------------------|
16. | 3 . Domestic |
17. | 3 . Domestic |
18. | 3 . Domestic |
19. | 3 . Domestic |
20. | 3 . Domestic |
|-----------------------------|
21. | 3 . Domestic |
22. | 3 . Domestic |
23. | 3 . Domestic |
24. | 3 . Domestic |
25. | 3 . Domestic |
|-----------------------------|
26. | 3 . Domestic |
27. | 3 . Domestic |
28. | 3 . Domestic |
29. | 3 . Domestic |
30. | 3 . Domestic |
|-----------------------------|
31. | 3 . Domestic |
32. | 3 . Domestic |
33. | 3 . Domestic |
34. | 3 . Domestic |
35. | 3 . Domestic |
|-----------------------------|
36. | 3 . Domestic |
37. | 3 . Domestic |
38. | 3 . Domestic |
39. | 3 . Domestic |
40. | 3 . Domestic |
|-----------------------------|
41. | 4 24.88889 Foreign |
42. | 4 24.88889 Foreign |
43. | 4 24.88889 Foreign |
44. | 4 24.88889 Foreign |
45. | 4 24.88889 Foreign |
|-----------------------------|
46. | 4 24.88889 Foreign |
47. | 4 24.88889 Foreign |
48. | 4 24.88889 Foreign |
49. | 4 24.88889 Foreign |
50. | 4 . Domestic |
|-----------------------------|
51. | 4 . Domestic |
52. | 4 . Domestic |
53. | 4 . Domestic |
54. | 4 . Domestic |
55. | 4 . Domestic |
|-----------------------------|
56. | 4 . Domestic |
57. | 4 . Domestic |
58. | 4 . Domestic |
59. | 5 26.33333 Foreign |
60. | 5 26.33333 Foreign |
|-----------------------------|
61. | 5 26.33333 Foreign |
62. | 5 26.33333 Foreign |
63. | 5 26.33333 Foreign |
64. | 5 26.33333 Foreign |
65. | 5 26.33333 Foreign |
|-----------------------------|
66. | 5 26.33333 Foreign |
67. | 5 26.33333 Foreign |
68. | 5 . Domestic |
69. | 5 . Domestic |
70. | . 14 Foreign |
|-----------------------------|
71. | . . Domestic |
72. | . . Domestic |
73. | . . Domestic |
74. | . . Domestic |
+-----------------------------+
Once we've got things in that sort order,
we can copy down from the non-missings
to the missings. We do this _within_
appropriate groups:
. bysort rep78 : replace meanmpg = meanmpg[_n-1] if mi(meanmpg)
(42 real changes made)
. list rep78 meanmpg foreign
+-----------------------------+
| rep78 meanmpg foreign |
|-----------------------------|
1. | 1 . Domestic |
2. | 1 . Domestic |
3. | 2 . Domestic |
4. | 2 . Domestic |
5. | 2 . Domestic |
|-----------------------------|
6. | 2 . Domestic |
7. | 2 . Domestic |
8. | 2 . Domestic |
9. | 2 . Domestic |
10. | 2 . Domestic |
|-----------------------------|
11. | 3 23.33333 Foreign |
12. | 3 23.33333 Foreign |
13. | 3 23.33333 Foreign |
14. | 3 23.33333 Domestic |
15. | 3 23.33333 Domestic |
|-----------------------------|
16. | 3 23.33333 Domestic |
17. | 3 23.33333 Domestic |
18. | 3 23.33333 Domestic |
19. | 3 23.33333 Domestic |
20. | 3 23.33333 Domestic |
|-----------------------------|
21. | 3 23.33333 Domestic |
22. | 3 23.33333 Domestic |
23. | 3 23.33333 Domestic |
24. | 3 23.33333 Domestic |
25. | 3 23.33333 Domestic |
|-----------------------------|
26. | 3 23.33333 Domestic |
27. | 3 23.33333 Domestic |
28. | 3 23.33333 Domestic |
29. | 3 23.33333 Domestic |
30. | 3 23.33333 Domestic |
|-----------------------------|
31. | 3 23.33333 Domestic |
32. | 3 23.33333 Domestic |
33. | 3 23.33333 Domestic |
34. | 3 23.33333 Domestic |
35. | 3 23.33333 Domestic |
|-----------------------------|
36. | 3 23.33333 Domestic |
37. | 3 23.33333 Domestic |
38. | 3 23.33333 Domestic |
39. | 3 23.33333 Domestic |
40. | 3 23.33333 Domestic |
|-----------------------------|
41. | 4 24.88889 Foreign |
42. | 4 24.88889 Foreign |
43. | 4 24.88889 Foreign |
44. | 4 24.88889 Foreign |
45. | 4 24.88889 Foreign |
|-----------------------------|
46. | 4 24.88889 Foreign |
47. | 4 24.88889 Foreign |
48. | 4 24.88889 Foreign |
49. | 4 24.88889 Foreign |
50. | 4 24.88889 Domestic |
|-----------------------------|
51. | 4 24.88889 Domestic |
52. | 4 24.88889 Domestic |
53. | 4 24.88889 Domestic |
54. | 4 24.88889 Domestic |
55. | 4 24.88889 Domestic |
|-----------------------------|
56. | 4 24.88889 Domestic |
57. | 4 24.88889 Domestic |
58. | 4 24.88889 Domestic |
59. | 5 26.33333 Foreign |
60. | 5 26.33333 Foreign |
|-----------------------------|
61. | 5 26.33333 Foreign |
62. | 5 26.33333 Foreign |
63. | 5 26.33333 Foreign |
64. | 5 26.33333 Foreign |
65. | 5 26.33333 Foreign |
|-----------------------------|
66. | 5 26.33333 Foreign |
67. | 5 26.33333 Foreign |
68. | 5 26.33333 Domestic |
69. | 5 26.33333 Domestic |
70. | . 14 Foreign |
|-----------------------------|
71. | . 14 Domestic |
72. | . 14 Domestic |
73. | . 14 Domestic |
74. | . 14 Domestic |
+-----------------------------+
More on the principle at
http://www.stata.com/support/faqs/data/missing.html
Nick
[email protected]
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