**************************************************************
* cfkids-derived.do                                          *
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*                                                            *  
* PURPOSE:  analysis of FEV1 among CF kids                   *
*                                                            *
* AUTHOR:  P. Heagerty                                       *
*                                                            *
* DATE:  31 March 2005                                       *  
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use NewCFkids

***
*** save kid-level data
***

collapse (mean) f508 gender age0, by(id)

save KidData, replace

clear
  
***
*** fit a line to each child's data
***

use NewCFkids

sort id

**** can't estimate line if less than 2 observations

by id: drop if _N < 2

statsby "reg fev1 ageL" _b, by(id)

list in 1/10

***** merge back with the KidData

merge id using KidData


*****
***** summarize  b_ageL and b_cons by covariates
*****

sort gender
by gender: summarize b_ageL
ttest b_ageL, by(gender)
graph box b_ageL, over(gender)

sort f508
by f508: summarize b_ageL
xi: reg b_ageL i.f508
graph box b_ageL, over(f508)