options crt;
out weird;
?Source: David Hamilton, "Sometimes R2 > r2yx1 + r2yx2:
?Correlated Variables Are Not Always Redundant,"
?THE AMERICAN STATISTICIAN, Vol. 41, No. 2, 
?May 1987, pp. 129-132.
load;
end;
noprint;
load
Y     X1    X2;
12.37  2.23  9.66
12.66  2.57  8.94
12.00  3.87  4.40
11.93  3.10  6.64
11.06  3.39  4.91
13.03  2.83  8.52
13.13  3.02  8.04
11.44  2.14  9.05
12.86  3.04  7.71
10.84  3.26  5.11
11.20  3.39  5.05
11.56  2.35  8.51
10.83  2.76  6.59
12.63  3.90  4.90
12.46  3.16  6.96