? P&R Exercise 9.6

options crt limwarn=0;
freq n;
set nobs=7*45;
smpl 1 nobs;
read(file='\tsp\prhb\datadisk\ex96.xls', format=excel) cusip p rnd;
lp=log(p);
panel(id=cusip) lp c rnd;
stop; end;