use chds

des

summarize

summarize weight msmoke mage, detail

	* create msmoke group variable ms_gp
generate ms_gp = 1 if msmoke == 0
replace ms_gp = 2 if msmoke >= 1 & msmoke < 20
replace ms_gp = 3 if msmoke >= 20
label define ms_gp_txt 1 "Nonsmoker" 2 "Less than a pack" 3 "Pack or more"
label values ms_gp ms_gp_txt


   * create mage group variable ma_gp
generate ma_gp = 1 if mage < 30
replace ma_gp = 2 if mage >= 30
label define ma_gp_txt 1 "Young" 2 "Mature"
label values ma_gp ma_gp_txt


tabulate ms_gp ma_gp, summarize(weight) means

   * fit anova
anova weight ms_gp ma_gp ms_gp*ma_gp
anova, regress

   * use xi to create indicator variables and fit using a regression
xi: regress weight i.ms_gp i.ma_gp i.ms_gp*i.ma_gp

   * xi default parameters (first ones zero)
char ms_gp[omit] 1
char ma_gp[omit] 1
xi: regress weight i.ms_gp i.ma_gp i.ms_gp*i.ma_gp

   * anova default parameters (last ones zero)
char ms_gp[omit] 3
char ma_gp[omit] 2
xi: regress weight i.ms_gp i.ma_gp i.ms_gp*i.ma_gp


test