(* PS6.5 using DATA6-3 for Example 6.4 *)
genr C1 = Cons(-1)
(* print C1 to see how it is stored internally; -999 means missing value *)
print Cons C1
(* generate DY(t) - DY(t-1) using the diff function *)
genr DiffI = diff(DI)
(* print DI and DiffI to see how they are stored internally *)
print DI DiffI
(* note that ols starts in 1949 because C1 & DiffI are undefined for
1948 *)
ols Cons 0 C1 DiffI
