options crt;  ? 7e4
in ukelec;
smpl 1,42;
f = expen - mc8*kwh/240;
avgpe = 240*expen/kwh;
lnf = log(f);
lnavpe = log(avgpe);  ? (a)
sh = f/inc;
msd sh;
set by2km = @mean;  ? (b)
lnx = log(kwh);
lnm = log(inc);
lnpe2 = log(mc6);
lnpg2 = log(gas6);
lnh = log(cap);
dot pe2 avpe;  ? try both lnpe2 and lnavpe for (f)
 ols(silent) lnf c lnm ln. lnpg2 lnh;
  set b21 = @coef(3);  ? coef of lnpe2
  print b21;  ? (c)
  set biasm = b21*by2km;
  print biasm;  ? (d)
 ols(silent) lnx c lnf lnm ln. lnpg2 lnh;
  set by1k. = @coef(4);
 ols(silent) lnx c     lnm ln. lnpg2 lnh;
  set by1 = @coef(3);
  set bias = by1 - by1k.;
  print by1 by1k. bias;  ? (e)
enddot;
lnincm = log(expen-f);
ols(silent) lnx c lnincm lnpe2 lnpg2 lnh;
  set by1km = @coef(3);
  print by1km,by1kpe2,by1kavpe;  ? (g)