Displaying 20 results from an estimated 400 matches similar to: "Is there a method to calculate Huynh and Feldt adjustments for sphericity violations"
2000 Aug 28
2
is win.print() broken or am I doing something wrong?
I am trying to print a graph
> plot(y=atestplot$b,x=atestplot$a, type="s")
> win.print()
This leads to a windows print dialog box- that diappears when i hit
print. subquently i find a
"GraphAppJob" of zero size in the print queue- this just sits until I
enter
dev.off()
at which point a blank sheet is printed
Is it me or is this a bug?
Incidentally if i just
2007 May 14
0
JOB: Biostatistician/Statistical Programmer/Data Analyst
Biostatistician/Statistical Programmer/Data Analyst
The Department of Biostatistics and Computational Biology, University
of Rochester Medical Center is seeking a Biostatistician/Statistical
Programmer/Data Analyst to assist with several center-wide immunology
and infectious disease research studies. The biostatistician will
work with senior statisticians and other senior biomedical
2007 May 14
0
JOB: Biostatistician/Statistical Programmer/Data Analyst
Biostatistician/Statistical Programmer/Data Analyst
The Department of Biostatistics and Computational Biology, University
of Rochester Medical Center is seeking a Biostatistician/Statistical
Programmer/Data Analyst to assist with several center-wide immunology
and infectious disease research studies. The biostatistician will
work with senior statisticians and other senior biomedical
2005 May 04
1
Huynh-Feldt R vs SAS Bug
Hi,
I'm using anova.mlm sphericity tests/corrections, and I'm getting
different values than SAS. In order to be able to use these values for
publications, I'd need to know more about the SAS bug that is mentioned
in the Reference Manual.
- What exactly causes the different values?
- Is it just a slight difference, or can I expect significant
differences in H-F/G-G epsilons and
2005 Feb 18
1
Two-factorial Huynh-Feldt-Test
Hi,
I'm currently working on porting some SAS scripts to R, and hence need
to do the same calculation (and get the same results) as SAS in order to
make the transition easier for users of the script.
In the script, I'm dealing with a two-factorial repeated-measures anova.
I'll try to give you a short overview of the setup:
- two between-cell factors: facBetweenROI (numbering
2007 Jun 24
2
ANOVA non-sphericity test and corrections (eg, Greenhouse-Geisser)
I'm an experimental psychologist and when I run ANOVA analysis in
SPSS, I normally ask for a test of non-sphericity (Box's M-test). I
also ask for output of the corrections for non-sphericity, such as
Greenhouse-Geisser and Huhn-Feldt. These tests and correction factors
are commonly used in the journals for experimental and other
psychology reports. I have been switching from SPSS to R
2009 Mar 03
1
repeated measures anova, sphericity, epsilon, etc
I have 3 questions (below).
Background: I am teaching an introductory statistics course in which we are
covering (among other things) repeated measures anova. This time around
teaching it, we are using R for all of our computations. We are starting by
covering the univariate approach to repeated measures anova.
Doing a basic repeated measures anova (univariate approach) using aov()
seems
2007 Mar 26
0
Sphericity and post-hoc analysis in a repeated-measure ANOVA
Does anyone have any suggestions for how to test for violation of the
sphericity assumption and apply the Huynh-Feldt correction to a
repeated-measure model? My model follows the format below:
Rep.anova=aov(Y~X1*X2+Error(Subject/(X1*X2),data=DataFile))
I've already looked at the explanations aov() and Error() in Baron's
“Notes on the use of R for psychology experiments and
2003 Dec 13
0
sphericity calculation (more formulas?)
I believe that the following function is a good function for eyeballing
sphericity. But, I can't find functions for tests anywhere (g-g or
h-f). Anyone who wants to can feel free to use it.
It is bad that R does not provide any tests for sphericity AND cannot
do a MANOVA on repeated measures (although lme is an alternative add on
package). One of these solutions must be provided in the
2006 Mar 20
1
does lme repeated measures require sphericity?
I haven't been able to find an answer on this that's direct, only
implied. In several places I have read that when people asked for
sphericity tests they were guided toward lme or mlm models. But,
there is no direct indication that the lme method is not subject to
the sphericity assumption. In fact, it seems like it should be. Its
just a linear model that handles random and
2007 Aug 21
2
Sphericity test in R for repeated measures ANOVA
Hi,
Is there a way to do a sphericity test in R for repeated measures ANOVA
(using aov or lme)? I can't find anything about it in the help.
Thanks
Orou
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2004 Jun 23
1
Sphericity test
Hi R-users
Does anybody know if there are functions or packages in R for sphericity
tests like Bartlett's or Mauchly's?
Thanks!
__________________________________________________________
Eng. Agr., M.Sc. Eduardo Dutra de Armas
__________________________________________________________
Centro de Energia Nuclear na Agricultura (CENA/USP)
Laboratório de Ecotoxicologia
Av.Centenário 303,
2005 May 10
1
sphericity calculation
Dear Prof. Baron,
thankyou for your pdf paper on using R, at
http://www.psych.upenn.edu/~baron/rpsych.pdf
I am currently interested in the sphericity notes on pp. 45-47.
The equation on p. 46 suggests the following R calculation:
D <- k^2 * ( mean(diag(S)) - mean(S) )^2
while the notes in the pdf indicate the following:
D <- k^2 * ( mean(S) - mean(diag(S)) )^2
Can you please consider
2011 Mar 10
1
power for repeated-measures ANOVA lacking sphericity
Is there a function that calculates the power of a
repeated-measure ANOVA design, e.g., 2 groups, 4
within-subject factors, an average 0.40 correlation between
the 4 within factors, etc.
I don't think I can use power.anova.test() because it does
not consider corr=0.40.
I am hoping that someone has already implemented the method
by Muller & Barton (1989, JASA 84: 549-555) on how to
2003 Dec 05
0
simple sphericity test using bartlett and cov?
Hey,
Is this right for a sphericity test?
x <- mymatrix
mycov <- cov(x)
bartlett.text (array (mycov), myconditions)
2009 Nov 09
1
Getting Sphericity Tests for Within Subject Repeated Measure Anova (using "car" package)
Hello everyone,
I am trying to do within subjects repeated measures anova followed by the
test of sphericity (sample dataset below).
I am able to get either mixed model or linear model anova and TukeyHSD, but
have no luck with Repeated-Measures Assuming Sphericity or Separate
Sphericity Tests.
I am trying to follow example from "car" package, but it seems that I am not
getting something
2009 Dec 01
0
GLM Repeated measures test of assumptions: e.g. test for sphericity e.g. Bartletts and Levenes homogenous variances
Hello and thanks in advance
I am running a glm in R the code is as follows with residual diagnostic code
below
model4<-glm(Biomass~(Treatment+Time+Site)^2, data=bobB,
family=quasi(link="log", variance="mu"))
par(mfrow=c(2,2))
plot(model2)
to test the effect of grazing exclusion of feral horses for a Phd with
following factors:
Treatment - 3 levels which are grazed
2005 May 11
1
2 factor ANOVA and sphericity
With respect to calculating the epsilon index of sphericity for ANOVA,
discussed on pp. 45-47 of:
http://www.psych.upenn.edu/~baron/rpsych.pdf
It notes that epsilon is not required for a repeated measures design with
only k=2 levels, as the minimum value of epsilon (e) is given by:
e = 1/(k-1)
so for k=2, we have e = 1 (ie, no correction of the F test df; see p. 46).
These notes apply to a
2009 Nov 09
1
Getting Sphericity Tests for Within Subject Repeated Measure Anova (using "car" package) (Adjusted Dataset)
[corrected dataset below]
Hello everyone,
I am trying to do within subjects repeated measures anova followed by the
test of sphericity (sample dataset below).
I am able to get either mixed model or linear model anova and TukeyHSD, but
have no luck with Repeated-Measures Assuming Sphericity or Separate
Sphericity Tests.
I am trying to follow example from "car" package, but it seems
2011 Jun 17
4
Bartlett's Test of Sphericity
Hello Dear R user,
I want to conduct a Principal components analysis and I need to run two
tests to check whether I can do it or not. I found how to run the KMO
test, however i cannot find an R fonction for the Bartlett's test of
sphericity. Does somebody know if it exists?
Thanks for your help!
Thibault
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