use "C:\452-554_Microeconometrics\MUS-datasets-dofiles\mus03data.dta", clear sum totexp return list gen ortalama = r(sum) / r(N) reg ltotexp income famsze educyr totchr ereturn list * to use only some observations reg ltotexp income famsze educyr totchr in 1/500 * if you want to keep only the first 500 observations in the dataset: * keep in 1/500 * create a dummy variable tabulate famsze, gen(fsdum) * the above creates a dummy for every different value of famsze summarize fsdum* drop fsdum* * the above drops all famsze dummy variables just created * or you can explicitly create the dummies one by one gen fsdum1= (famsze==1) gen fsdum2= (famsze==2) gen fsdum3= (famsze==3) drop fsdum* * a 3rd alternative is to explicitly create the dummies using generate/replace commands gen fsdum1= 1 if (famsze==1) replace fsdum1= 0 if (famsze!=1) gen fsdum2= 1 if (famsze==2) replace fsdum1= 0 if (famsze!=2) gen fsdum3= 1 if (famsze==3) replace fsdum1= 0 if (famsze!=3) * to see the prob density function of a varable kdensity totexp kdensity ltotexp