[R] ANOVA and Levene's test in nested model

2006-10-17 Thread Emilia Pippola

Dear All,

I sent already before a message concerning Levene's test in nested model,
but I didn't get any answer. Optimistically I hope to get an answer this
time. I also point a new question related to the whole model, because I
haven't find any sure answer if I am analysing it in a suitable way or
not. I really have tried to do my homework.

I have response variable (y) and four factors (a, b, c, d). One of
these four factors (d) is nested within another factor (c). In addition,
I would like to take into account only 2nd degree interactions in my
model.

I tried to analyse this model in the following ways (both gave same
results):

 model1-aov(y~(a+b+c)^2 + Error(d))

 model2-aov(y~(a+b+c)^2 + Error(d%in%c))

Is this correct?


I guess another option would be lme in package nlme

 model3-lme(y~(a+b+c)^2, random=~1|d)
 anova(model3)


I am also willing to test homogenity of variances in this model using
Levene's test. How to do it in this kind of case?


I'll appreciate all advices.

With kind regards

-Emilia

-
Emilia Pippola, research assistant
University of Oulu

Personal address (NEW!):
Rautalammintie 3 B 306
FIN-00550 Helsinki, Finland

Mobile: +358-50-5402551
E-mail: [EMAIL PROTECTED]

__
R-help@stat.math.ethz.ch mailing list
https://stat.ethz.ch/mailman/listinfo/r-help
PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
and provide commented, minimal, self-contained, reproducible code.


[R] Details related to Levene's test

2006-10-11 Thread Emilia Pippola

Dear All,

I am willing to test homogenity of variances using Levene's test. I know
how to do it with simple model, but I am lost when dealing with a
little bit more complex model.

I have response variable (y) and four factors (a, b, c, d). One of
these four factors (d) is nested within another factor (c). In addition,
I would like to take into account only 2nd degree interactions in my
model.

How to do Levene's test in this kind of case?

I'll appreciate all advices.

With kind regards

-Emilia

-
Emilia Pippola, research assistant
University of Oulu

Personal address (NEW!):
Rautalammintie 3 B 306
FIN-00550 Helsinki, Finland

Mobile: +358-50-5402551
E-mail: [EMAIL PROTECTED]

__
R-help@stat.math.ethz.ch mailing list
https://stat.ethz.ch/mailman/listinfo/r-help
PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
and provide commented, minimal, self-contained, reproducible code.