Compute average of m variables where m is a variable in the data file

* Compute avg of m varaibles where m is a variable in the data file.
* in the example m is gmplans. Thus in second case (gmplans=2) we want the average of the first two variables,
  that is variables fpr_iy1 and fpr_ip2.
* Raynald Levesque Feb 2004.
* http://pages.infinit.net/rlevesqu/index.htm

NEW FILE.
DATA LIST LIST /gmplans fpr_iy1 TO fpr_iy4.
BEGIN DATA
1 4 3 2 1
2 4 3 2 1 
3 4 3 2 1 
4 4 3 2 1
0 4 3 2 1
END DATA.

VECTOR v1 = fpr_iy1 TO fpr_iy4 .
LOOP #i = 1 TO gmplans.
- DO IF #i=1.
-    COMPUTE min_ind = v1(#i) .
- ELSE.
-    COMPUTE min_ind=MIN(min_ind, v1(#i)).
- END IF.
END LOOP .

DESCRIPTIVES
  VARIABLES=min_ind
  /STATISTICS=MEAN STDDEV MIN MAX .