On 06 Jul 2015, at 18:17 , John Fox <jfox at mcmaster.ca> wrote:
Dear Angelo,
One way to do this is with the Anova() function in the car package; see the
following article in the R Journal:
@Article{RJournal:2013-1:fox-friendly-weisberg,
author = {John Fox and Michael Friendly and Sanford Weisberg},
title = {Hypothesis Tests for Multivariate Linear Models Using the
{car} Package},
journal = {The R Journal},
year = 2013,
volume = 5,
number = 1,
pages = {39--53},
month = jun,
url =
{http://journal.r-project.org/archive/2013-1/RJournal_2013-1_fox-friendly-we
isberg.pdf}
I hope this helps,
John
-----------------------------------------------
John Fox, Professor
McMaster University
Hamilton, Ontario, Canada
http://socserv.socsci.mcmaster.ca/jfox/
-----Original Message-----
From: R-help [mailto:r-help-bounces at r-project.org] On Behalf Of
angelo.arcadi at virgilio.it
Sent: July-06-15 10:05 AM
To: r-help at r-project.org
Subject: [R] Sphericity for a repeated measure ANOVA with whithin and
between subjects design, using R
Dear List Members,
I need to perform a four-way ANOVA with repeated measures and to
calculate the sphericity for eventual correction of the degree of
freedom of the F ratio.
I have three within subjects factors (Emotion, having 5 levels,
Material, having 4 levels, Shoes, having 2 levels) and a between subject
factor (Musician, having 2 levels). Without considering the sphericity
I
use the following formula
aov_SPL = aov(SPL ~ Emotion*Material*Shoes*Musician +
Error(Subject/(Emotion*Material*Shoes)), data=scrd)
Unfortunately after having read lot of material online I did not
arrive to a solution about how to calculate for my case the epsilon of
the Greenhouse-Geisser method for degree of freedom adjustment.
I load my data in R with this formula:
scrd<- read.csv(file='/path to data/data.csv',sep=',',header=T)
and this is the structure of the imported table:
Subject Material Shoes Emotion H2H H2H_factor SPL_factor
SPL_variation SPL Musician Weight Height
1 Subject1 Gravel dress_shoes AGGRESSIVE 468 0.736 11.591
21.283 97.383 no 90 183
2 Subject1 Gravel dress_shoes HAPPY 719 1.129 3.188
10.071 86.171 no 90 183
3 Subject1 Gravel dress_shoes TENDER 1129 1.774 5.114
14.176 90.276 no 90 183
4 Subject1 Gravel dress_shoes SAD 1010 1.587 13.102
22.347 98.447 no 90 183
5 Subject1 Gravel dress_shoes NEUTRAL 736 1.156 3.161
9.995 86.095 no 90 183
6 Subject10 Gravel dress_shoes AGGRESSIVE 635 0.998 15.849
24.000 100.100 yes 70 178
I noticed that in the car package there is the Anova() function that
comes with the Maulchy's sphericity test, but it does not take as an
input a model generated with aov(). I need to use lm() instead, but
since
I am not really proficient in R I do not know how to use the lm()
starting from the loaded data and how to use Anova(). In addition, being
a mixed design involving within and between subjects factors I wonder
if Anova() is the most appropriate function to use for my case.
Is there anyone who could provide me with the R code to calculate the
Maulchy's test and the epsilon of Greenhouse-Geisser for my case?
Thank you in advance
Best
Angelo
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