st: predicting height by age for each individual

["Y.R.E. Retamal" <yrer2@cam.ac.uk>]

Dear STATA users

I am studying growth and development in children from 0 to 3 years old. 
I am using a longitudinal database of children where height and weight 
were measured from birth to three years old (1600 children).
I would like to predict height of each child from birth until three 
years old for each six months (birth, 6, 12, 18, ..., 36 month), after 
running a linear regression of height by age for each child, not all at 
the same time.
For example, I have the following database:

id	month	height
1	0	59
1	6	68
1	12	70
1	18	74
1	24	81
1	30	86
1	36	94
2	0	50
2	6	55
2	12	74
2	18	80
2	24	82
2	30	87
2	36	95


I could do:
reg height month if id==1
predict xb if id!=1
reg height month if id==2
predict xb if id!=2

and so...

But, I have 1600 children, therefore I should write the same commands 
per each child (1600 times), something truly inefficient and tedious. 
There is a command or program to run the same commands, but 
automatically?


Any help would be very appreciated.
Rodrigo

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