<br />
a<-1:12<br />
> b<-rnorm(12)<br />
> e<-data.frame(a,b)<br />
> g<-lm(a~b,e)<br />
> model.matrix(g)<br />
(Intercept) b<br />
1 1 -0.51861581<br />
2 1 0.40635687<br />
3 1 0.08892921<br />
4 1 0.22532893<br />
5 1 0.86566219<br />
6 1 0.34308603<br />
7 1 -0.05266934<br />
8 1 1.07944865<br />
9 1 0.14454437<br />
10 1 -1.02273617<br />
11 1 0.43514432<br />
12 1 0.86351736<br />
attr(,"assign")<br />
[1] 0 1<br />
> model.frame(g)<br />
a b<br />
1 1 -0.51861581<br />
2 2 0.40635687<br />
3 3 0.08892921<br />
4 4 0.22532893<br />
5 5 0.86566219<br />
6 6 0.34308603<br />
7 7 -0.05266934<br />
8 8 1.07944865<br />
9 9 0.14454437<br />
10 10 -1.02273617<br />
11 11 0.43514432<br />
12 12 0.86351736<br />
> b<br />
[1] -0.51861581 0.40635687 0.08892921 0.22532893 0.86566219 0.34308603 -0.05266934 1.07944865 0.14454437 -1.02273617<br />
[11] 0.43514432 0.86351736<br />
> g<br />
<br />
Call:<br />
lm(formula = a ~ b, data = e)<br />
<br />
Coefficients:<br />
(Intercept) b <br />
6.2673 0.9772 <br />
<br />
model.matrix(g),那两列分别是什么东西?