Displaying 5 results from an estimated 5 matches for "mlmfit0".
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mlmfit
2008 Sep 09
1
How do I compute interactions with anova.mlm ?
...factors.
I suspect, I have to create a new "grouping" factor and then test with this factor to get these interactions (as it is hinted in R News 2007/2),
but I don't really know how to use this approach.
Here is my current code:
Two Factors: fac1, fac2
mlmfit <- lm(mydata~1)
mlmfit0 <- update(mlmfit, ~0)
% test fac1, works, produces same output as SAS
anova(mlmfit, mlmfit0, M = ~ fac1 + fac2, X = ~ fac2, idata = idata, test = "Wilks")
% test fac1*fac2 interaction, also works, also the same output as SAS
anova(mlmfit, mlmfit0, X = ~ fac1 + fac2, idata = idata, te...
2005 May 25
2
Weird function call problem
Hi,
I'm encountering a very odd problem with calls to anova.mlm() from within a
function.
Consider the following code (data.n is a matrix of numeric values):
mlmfit <- lm(data.n ~ 1)
mlmfit0 <- lm(data.n ~ 0)
print(mlmfit)
anova(mlmfit,mlmfit0,test="Spherical")
If I run it just like this from the console, it works just fine. If,
however, I call it from within a function, e.g. using
fct <- function(data.k) {
# same code with data.n replaced by data.k
}
fct(data.n)
It...
2005 Nov 15
1
Repeates Measures MANOVA for Time*Treatment Interactions
...up using the anova.mlm approach
so that in the end I can write up a table that says
Treatment
Time
Time*Treatment
I can see from ?anova.mlm how one would get the Treatment effect using
something like
response<-with(my.data, rbind(Time1, Time2, Time3, Time4, Time5))
mlmfit<-lm(response~1)
mlmfit0<-update(mlmfit, ~0)
anova(mlmfit, mlmfit0, X = ~ Treatment, idata=my.data, test="Spherical")
Although this yields the result that, after correction, it's not
significant - perhaps due to the low DF from this simple example
--
Analysis of Variance Table
Model 1: response ~ 1
Mode...
2005 Jun 15
1
Anohter anova.mlm problem
Hi,
yet another anova.mlm problem - it doesn't seem to end.
This time, I have a setup with a few within-subject factors and a
between-subject factor (SGROUP). Consider the most simple case with only one
within-factor (apo):
> mlmfit0 <- lm(data.n ~ 0 + SGROUP)
> mlmfit1 <- lm(data.n ~ 1 + SGROUP)
> anova(mlmfit1,mlmfit0,test="Spherical",M=~hemi,X=~1)
Analysis of Variance Table
Model 1: data.n ~ 1 + SGROUP
Model 2: data.n ~ 0 + SGROUP
Contrasts orthogonal to
~1
Contrasts spanned by
~hemi
Greenhouse-Gei...
2007 May 13
2
Some questions on repeated measures (M)ANOVA & mixed models with lme4
...+ Error(subj+subj:time))
(from: http://cran.r-project.org/doc/contrib/Baron-rpsych.pdf, p. 41)
C. "Repeated measures" MANOVA as follows (using data in wide format):
response <- cbind(time1,time2,time3,time4,time5,time6)
mlmfit <- lm(response ~ group)
mlmfit1 <- lm(response ~ 1)
mlmfit0 <- lm(response ~ 0)
# Test time*group effect
anova.mlm(mlmfit, mlmfit1, X=~1, test="Spherical")
# Test overall group effect
anova.mlm(mlmfit, mlmfit1, M=~1)
# Test overall time effect
anova.mlm(mlmfit1, mlmfit0, X=~1, test="Spherical")
(taken from http://tolstoy.newcastle.ed...