I'm curious, I realize there are methods for Type II and III sums of
squares, and yet, when I've been constructing models with lm, I've
noticed that position of the term of the model has not mattered in
terms of its p-value. Does lm use sequential Type I sums of squares,
or something else?
Dear Jarrett,
anova() gives sequential sums of squares (as ?anova.lm says). See
Anova() in the car package for something similar to Type II and III
sums of squares.
I hope this helps,
John
On Fri, 28 Oct 2005 10:05:39 -0700
Jarrett Byrnes [EMAIL PROTECTED] wrote:
I'm curious, I realize there
anova.lm() gives the sequential tests:
set.seed(1)
dat - data.frame(y=rnorm(10), x1=runif(10), x2=runif(10))
anova(lm(y ~ x1 + x2, dat))
Analysis of Variance Table
Response: y
Df Sum Sq Mean Sq F value Pr(F)
x1 1 1.1483 1.1483 2.0943 0.1911
x2 1 0.4972 0.4972
