options crt;  ? 5e2
in cps78;
smpl 1,550;
olsq lnwage c ed;             ? (a)
 rename @ssr ssr1;
olsq lnwage c union ed;       ? (b)
nonu = 1-union;
olsq lnwage nonu union ed;    ? (c)
 set tstat = sqrt( (ssr1-@ssr)/1/(@ssr/(@nob-3)) );
 print tstat;
olsq lnwage c nonu union ed;  ? (d)
olsq lnwage c nonu ed;        ? (e)
?
delete lnwage ed union;
in cps85;
smpl 1,534;
olsq lnwage c ed;             ? (a)
 rename @ssr ssr1;
olsq lnwage c union ed;       ? (b)
nonu = 1-union;
olsq lnwage nonu union ed;    ? (c)
 set tstat = sqrt( (ssr1-@ssr)/1/(@ssr/(@nob-3)) );
 print tstat;
olsq lnwage c nonu union ed;  ? (d)
olsq lnwage c nonu ed;        ? (e)