clear
set more off
cd "~/Documents/teaching/c2015/biostat208/labs/lab7"
* do "~/Documents/teaching/c2015/biostat208/labs/lab7/lab7.do"
capture log close
log using lab7, replace
use lab7, clear

* a priori model
regress bmd eeu age lweight i.estrogen calsupp diuretic etid momhip usearms ///
	gs10 gaitspd poorhlth caffeine drnkspwk smoker 
	
* cic model selection
cic,  model(regress) outcome(bmd) primary(eeu) ///
   alist(age lweight i.estrogen calsupp diuretic etid momhip) ///
   blist(usearms i.tandstnd has10 gs10 gaitspd poorhlth caffeine drnkspwk smoker) 
	
lincom eeu*1.5
lincom eeu*1.5/0.73*100
lincom 2.estrogen
nlcom _b[lweight]*log(1.1)

cic, model(regress) outcome(bmd) primary(eeu) ///
   alist(age lweight i.estrogen calsupp diuretic etid momhip) ///
   blist(usearms i.tandstnd has10 gs10 gaitspd poorhlth caffeine drnkspwk smoker) ///
   complete 
   
cic, model(regress) outcome(bmd) primary(eeu) ///
   alist(age lweight i.estrogen calsupp diuretic etid momhip) ///
   blist(usearms i.tandstnd has10 gs10 gaitspd poorhlth caffeine drnkspwk smoker) ///
   criterion(10)
	

* backwards: 
xi: sw, lockterm1 pr(0.2): ///
	regress bmd (eeu age lweight i.estrogen calsupp diuretic etid momhip) ///
    usearms (i.tandstnd) has10 gs10 gaitspd poorhlth caffeine drnkspwk smoker
    
* Allen Cady procedure: 
xi: sw, lockterm1 pr(0.2) hier: ///
	regress bmd (eeu age lweight i.estrogen calsupp diuretic etid momhip) ///
    usearms (i.tandstnd) has10 gs10 gaitspd poorhlth caffeine drnkspwk smoker
    
* stepwise models with retention criteria of 0.2, 0.1, and 0.05
foreach pr in 0.2 0.1 0.05 {
   di _newline as result "Backwards deletion with a retention criterion of p<`pr'"
   xi: sw, lockterm1 pr(`pr'): ///
       regress bmd (eeu age lweight i.estrogen calsupp diuretic etid momhip) ///
       usearms (i.tandstnd) has10 gs10 gaitspd poorhlth caffeine drnkspwk smoker
       }	
* backwards selection model omitting tandem stand and hip abductor strength
xi: sw, lockterm1 pr(0.2): ///
	regress bmd (eeu age lweight i.estrogen calsupp diuretic etid momhip) ///
	usearms gs10 gaitspd poorhlth caffeine drnkspwk smoker

    
log close