options linesize=80;
options pagesize=60;


filename galluprw "./gallup.txt";

data gallup;
  infile galluprw;
  input loc age race gend educ emp wage hours
        weeks salary income disloc train monthu 
        rate;

  /* get to employed, males age 20-50 */
  if emp  NE  1 then delete;
  if age  LT 20 then delete;
  if age  GT 50 then delete;
  if gend NE  1 then delete;

  /* make the years of schooling variable */
  yrschool=8;
  if educ eq 4 then yrschool = 10;
  if educ eq 5 then yrschool = 12;
  if educ eq 6 then yrschool = 14;
  if educ eq 7 then yrschool = 14;
  if educ eq 8 then yrschool = 16;

proc means;

proc reg;
  model wage = hours age yrschool;

proc reg;
  model wage = hours age yrschool;
  restrict age-4*hours=0;