clear

set seed 15

set obs 1000

/* Effect of smoking intensity on lung cancer, modified by family history */
gen id = _n

// I wanted an OR for my main effect of 10.  I then wanted the effect to be
// modified by having family history.  Based on how I created the variables,
// The OR shoots up when stratifying by family history.

gen smok_inten= runiform()<=0.3
gen lung_ca =.
replace lung_ca=runiform()>=0.05 if smok_inten==0
replace lung_ca=runiform()>=0.37 if smok_inten==1

gen fam_hx =.
replace fam_hx =runiform()>=0.7

generate random =runiform()

sort random
generate insample1 = _n <= 100
generate insample2 = _n >= 101 & _n <= 200
generate insample3 = _n >= 201 & _n <= 300
generate insample4 = _n >= 301 & _n <= 400
generate insample5 = _n >= 401 & _n <= 500
generate insample6 = _n >= 501 & _n <= 600
generate insample7 = _n >= 601 & _n <= 700
generate insample8 = _n >= 701 & _n <= 800
generate insample9 = _n >= 801 & _n <= 900
generate insample10 = _n >= 901 & _n <= 1000

foreach var of varlist insample* {
logistic lung_ca smok_inten if `var' == 1
sort fam_hx
cc lung_ca smok_inten if `var'==1, by(fam_hx) 
}

// Setting the effect to Null

clear

set seed 15

set obs 1000

/* Effect of smoking intensity on lung cancer, modified by family history */
gen id = _n

gen smok_inten= runiform()<=0.3
gen lung_ca =.
replace lung_ca=runiform()>=0.5 if smok_inten==0
replace lung_ca=runiform()>=0.5 if smok_inten==1

gen fam_hx =.
replace fam_hx =runiform()>=0.7

generate random =runiform()

sort random
generate insample1 = _n <= 100
generate insample2 = _n >= 101 & _n <= 200
generate insample3 = _n >= 201 & _n <= 300
generate insample4 = _n >= 301 & _n <= 400
generate insample5 = _n >= 401 & _n <= 500
generate insample6 = _n >= 501 & _n <= 600
generate insample7 = _n >= 601 & _n <= 700
generate insample8 = _n >= 701 & _n <= 800
generate insample9 = _n >= 801 & _n <= 900
generate insample10 = _n >= 901 & _n <= 1000

foreach var of varlist insample* {
logistic lung_ca smok_inten if `var' == 1
sort fam_hx
cc lung_ca smok_inten if `var'==1, by(fam_hx) 
}