options double nwidth=20 signif=8 crt;  ? double is used to store
      ? data in double precision (series BIG and LITTLE have 8 significant
      ? digits; single precision can only represent 6-7 digits).
      ? Also, the polynomial terms X8 and X9 have a large number of
      ? significant digits (X9 has 9 significant digits).
      ? Nwidth and Signif are used to print more than the usual digits
name nasty "Wilkinson's Statistics Quiz, Sections II-IV";
load;

?***  II  ***
title 'round - II.A';
write(format='(F3.0)') round;   ? rounds to even numbers on Sun, rounds up
                                ? on PC and VAX
title 'round - II.A.2';
set y1 = int(2.6*7 - 0.2);  set y1t=18;
set y2 = 2-int(exp(log(sqrt(2)*sqrt(2))));  set y2t=0;
set y3 = int(3-exp(log(sqrt(2)*sqrt(2))));  set y3t=1;  ? yields 0 on Sun
print y1-y3;
print y1t-y3t;

? II.B
graph huge tiny;   ? the axis labels for HUGE are ********  (i.e. off scale)
graph big little;
graph x zero;

list all x zero miss big little huge tiny round;
? II.C
msd x zero big little huge tiny round;   ? drop out MISS by hand; otherwise
           ? the default will drop all observations.
           ? This crashes (overflow) on the VAX, when trying to compute
           ? the Kurtosis of HUGE, although this was not requested for II.C
?msd(byvar) all;   ? Alternative - override the default to compute stats
                   ? on each variable separately.

? II.D
corr x zero big little huge tiny round;   ? same comments as above
           ? Note: computes Corr(ZERO,*) = 0, rather than missing.
           ?  (perhaps this should be fixed...)
?corr(pairwise) all;   ? Alternative

? II.E  -- tabulate X against X with weight BIG, and HUGE against TINY
?  (no crosstab feature in TSP)

olsq big c x;  ? II.F

?***  III  ***
? III.A
test = 1*(miss=3) + 2*(miss .ne. 3);    ? this is the standard way of
              ? doing such recoding in TSP.  TEST is always missing
print test;   ? (which Wilkinson and Sawitzki note is consistent)

? III.B
select miss(miss);
miss = miss + 1;
print miss;

? III.C  -- tabulate MISS against ZERO
?  (no crosstab feature in TSP)

?***  IV  ***
dot(value=i) 2-9;
  x. = x**i;
enddot;
olsq x c x2-x9;  ? IV.A    Results agree with Sawitzki, but he doesn't
                 ?  state how he computed them.  They differ from SYSTAT.
olsq x c x;  ? IV.B
olsq x c big little;  ? IV.C
olsq zero c x;  ? IV.D

? Check number of significant digits in X9 (this is why the default
? single precision data storage does not yield quite the same results
? as IV.A on double precision data).
options nodouble;
x9s = x9;
res9 = x9 - x9s;
msd(terse) x9 x9s res9;   ? X9 has 9 significant digits

end;

noprint;
smpl 1,9;   ? note:  MISS and ROUND are reserved function names in TSP,
            ?  so they result in warning messages here.
read x zero miss big little huge tiny round;
1 0 . 99999991 0.99999991 1.0E12 1.0E-12 0.5
2 0 . 99999992 0.99999992 2.0E12 2.0E-12 1.5
3 0 . 99999993 0.99999993 3.0E12 3.0E-12 2.5
4 0 . 99999994 0.99999994 4.0E12 4.0E-12 3.5
5 0 . 99999995 0.99999995 5.0E12 5.0E-12 4.5
6 0 . 99999996 0.99999996 6.0E12 6.0E-12 5.5
7 0 . 99999997 0.99999997 7.0E12 7.0E-12 6.5
8 0 . 99999998 0.99999998 8.0E12 8.0E-12 7.5
9 0 . 99999999 0.99999999 9.0E12 9.0E-12 8.5
;