From: Purposeful selection of variables in logistic regression
n
Purposeful
Stepwise
Backward
Forward
60
5.1
4.5
4.9
9
120
24.2
22.4
22.8
240
52.6
52.5
36
360
69.8
42.5
480
71.1
71.2
44.2
600
70.5
70.6
40.4