Re: [R] Getting Sphericity Tests for Within Subject Repeated Measure Anova (using car package)
Dear John, thanks for your help and sorry for answering this late. My question is a follow up question of an older thread posted several mongths ago, but your statement helped a lot. Thanks, Max - M a x i m i l i a n M ue l l e r PhD-Student Department of Business Studies Leuphana Universität Lüneburg -- View this message in context: http://r.789695.n4.nabble.com/Getting-Sphericity-Tests-for-Within-Subject-Repeated-Measure-Anova-using-car-package-tp841030p4285034.html Sent from the R help mailing list archive at Nabble.com. __ R-help@r-project.org 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.
Re: [R] Getting Sphericity Tests for Within Subject Repeated Measure Anova (using car package)
On 1/3/2012 9:36 PM, maximilian.mueller wrote: Here is the syntax: options(contrasts=c(contr.sum, contr.poly)) read.csv2(test21.csv) - dat3 mod3 - lm(cbind(umsatz_t1, umsatz_t2, umsatz_t3, umsatz_t4) + cbind(ebitda_t1, ebitda_t2, ebitda_t3, ebitda_t4) + ~ 1, data=dat3) idata3 - data.frame(Umsatz=factor(1:4), EBITDA=factor(1:4)) aov3 - Anova(mod3, idata=idata3, idesign= ~Umsatz+EBITDA, type=III) Fehler in check.imatrix(X.design) : Terms in the intra-subject model matrix are not orthogonal. summary(aov3, multivariate=F) That's because you've defined two identical factor variables. idata3- data.frame(Umsatz=factor(1:4), EBITDA=factor(1:4)) idata3 - data.frame(Umsatz=factor(1:4), EBITDA=factor(1:4)) idata3 Umsatz EBITDA 1 1 1 2 2 2 3 3 3 4 4 4 If your data is a doubly-multivariate design with two repeated variables Umsatz and EBIDTA crossed with 4 time points each, you might want to look at the vignette HE Plots for Repeated Measures Designs in the heplots package for theory and examples vignette(repeated, package=heplots) -- Michael Friendly Email: friendly AT yorku DOT ca Professor, Psychology Dept. York University Voice: 416 736-5115 x66249 Fax: 416 736-5814 4700 Keele StreetWeb: http://www.datavis.ca Toronto, ONT M3J 1P3 CANADA __ R-help@r-project.org 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.
Re: [R] Getting Sphericity Tests for Within Subject Repeated Measure Anova (using car package)
Dear Max, I'm having a little trouble following what you did and am also confused by the subject of your posting. Is this a response to another message? Is it really about getting sphericity tests? In addition: (1) Why are you adding together the response matrices cbind(umsatz_t1, umsatz_t2, umsatz_t3, umsatz_t4) and cbind(ebitda_t1, ebitda_t2, ebitda_t3, ebitda_t4)? (2) From the names of the responses, I imagine that you have two, crossed, repeated-measures factors: umsatz vs. ebita, and times 1 through 4. If that's correct, then the intra-subject data should look like idata3 - data.frame( condition=rep(c(umsatz, ebita), each=5), time=ordered(rep(1:5, 2))) and the intra-subject design should be ~condition*time. Best, John John Fox Senator William McMaster Professor of Social Statistics Department of Sociology McMaster University Hamilton, Ontario, Canada http://socserv.mcmaster.ca/jfox -Original Message- From: r-help-boun...@r-project.org [mailto:r-help-bounces@r- project.org] On Behalf Of maximilian.mueller Sent: January-03-12 9:36 PM To: r-help@r-project.org Subject: Re: [R] Getting Sphericity Tests for Within Subject Repeated Measure Anova (using car package) Hello everyone, I am also trying to do within subjects repeated measures anova followed by the test of sphericity (see sample dataset attached below) and I am facing some problems. I tried to assign the example to my research question, but could not really solve it. Here is the syntax: options(contrasts=c(contr.sum, contr.poly)) read.csv2(test21.csv) - dat3 mod3 - lm(cbind(umsatz_t1, umsatz_t2, umsatz_t3, umsatz_t4) + cbind(ebitda_t1, ebitda_t2, ebitda_t3, ebitda_t4) + ~ 1, data=dat3) idata3 - data.frame(Umsatz=factor(1:4), EBITDA=factor(1:4)) aov3 - Anova(mod3, idata=idata3, idesign= ~Umsatz+EBITDA, type=III) Fehler in check.imatrix(X.design) : Terms in the intra-subject model matrix are not orthogonal. summary(aov3, multivariate=F) with the data set dat3 dat3 umsatz_t1 umsatz_t2 umsatz_t3 umsatz_t4 ebitda_t1 ebitda_t2 ebitda_t3 1 0.10239021 0.18241379 0.28875806 0.28875806 0.07622154 0.05543311 0.06776469 2 0.10239021 1.21769038 0.05840222 0.05840222 0.04794192 0.04642960 0.03727069 3 0.05124775 0.65373713 0.25976771 0.25976771 0.04794192 0.04435191 0.03167950 4 0.10239021 0.18241379 0.28875806 0.28875806 0.07622154 0.05543311 0.06776469 5 0.10239021 1.21769038 0.05840222 1.21769038 0.04794192 0.04642960 0.03727069 6 0.06776469 0.28875806 0.06776469 0.65373713 0.07622154 0.18241379 0.10239021 7 0.03727069 0.05840222 0.03727069 0.18241379 0.04794192 0.25976771 0.04794192 8 0.03727069 0.25976771 0.06776469 1.21769038 0.04557920 0.65373713 0.07622154 9 0.06776469 0.28875806 0.06776469 0.28875806 0.07622154 0.18241379 0.04794192 10 0.03727069 0.05840222 0.03727069 0.05840222 0.04794192 0.04642960 0.04557920 11 0.25976771 0.05543311 0.03727069 0.05543311 0.07622154 0.06776469 0.03167950 12 0.28875806 0.04642960 0.07622154 0.04642960 0.04794192 0.03727069 0.06776469 13 0.05840222 0.18241379 0.04794192 0.25976771 0.07622154 0.03167950 0.03727069 14 0.06776469 1.21769038 0.07622154 0.28875806 0.04794192 0.06776469 0.04642960 15 0.03727069 0.28875806 0.03727069 0.03727069 0.06776469 0.03727069 0.04435191 16 0.04794192 0.04642960 0.04557920 0.04557920 0.06776469 0.28875806 0.06776469 17 0.07622154 0.06776469 0.03167950 0.07622154 0.03727069 0.05840222 0.03727069 18 0.04794192 0.04642960 0.03727069 0.04435191 0.07622154 0.03167950 0.03727069 19 0.04794192 0.04435191 0.03167950 0.05543311 0.04794192 0.06776469 0.04642960 ebitda_t4 1 0.04642960 2 0.04435191 3 0.05543311 4 0.04642960 5 0.18241379 6 0.25976771 7 0.04794192 8 0.07622154 9 0.04794192 10 0.04557920 11 0.07622154 12 0.04794192 13 0.04557920 14 0.03167950 15 0.03167950 16 0.65373713 17 0.18241379 18 0.04557920 19 0.03167950 Thanks four your help... Sincerely, Max - M a x i m i l i a n M ue l l e r PhD-Student Department of Business Studies Leuphana Universität Lüneburg -- View this message in context: http://r.789695.n4.nabble.com/Getting- Sphericity-Tests-for-Within-Subject-Repeated-Measure-Anova-using-car- package-tp841030p4259642.html Sent from the R help mailing list archive at Nabble.com. __ R-help@r-project.org 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-help@r-project.org 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.
Re: [R] Getting Sphericity Tests for Within Subject Repeated Measure Anova (using car package)
Hello everyone, I am also trying to do within subjects repeated measures anova followed by the test of sphericity (see sample dataset attached below) and I am facing some problems. I tried to assign the example to my research question, but could not really solve it. Here is the syntax: options(contrasts=c(contr.sum, contr.poly)) read.csv2(test21.csv) - dat3 mod3 - lm(cbind(umsatz_t1, umsatz_t2, umsatz_t3, umsatz_t4) + cbind(ebitda_t1, ebitda_t2, ebitda_t3, ebitda_t4) + ~ 1, data=dat3) idata3 - data.frame(Umsatz=factor(1:4), EBITDA=factor(1:4)) aov3 - Anova(mod3, idata=idata3, idesign= ~Umsatz+EBITDA, type=III) Fehler in check.imatrix(X.design) : Terms in the intra-subject model matrix are not orthogonal. summary(aov3, multivariate=F) with the data set dat3 dat3 umsatz_t1 umsatz_t2 umsatz_t3 umsatz_t4 ebitda_t1 ebitda_t2 ebitda_t3 1 0.10239021 0.18241379 0.28875806 0.28875806 0.07622154 0.05543311 0.06776469 2 0.10239021 1.21769038 0.05840222 0.05840222 0.04794192 0.04642960 0.03727069 3 0.05124775 0.65373713 0.25976771 0.25976771 0.04794192 0.04435191 0.03167950 4 0.10239021 0.18241379 0.28875806 0.28875806 0.07622154 0.05543311 0.06776469 5 0.10239021 1.21769038 0.05840222 1.21769038 0.04794192 0.04642960 0.03727069 6 0.06776469 0.28875806 0.06776469 0.65373713 0.07622154 0.18241379 0.10239021 7 0.03727069 0.05840222 0.03727069 0.18241379 0.04794192 0.25976771 0.04794192 8 0.03727069 0.25976771 0.06776469 1.21769038 0.04557920 0.65373713 0.07622154 9 0.06776469 0.28875806 0.06776469 0.28875806 0.07622154 0.18241379 0.04794192 10 0.03727069 0.05840222 0.03727069 0.05840222 0.04794192 0.04642960 0.04557920 11 0.25976771 0.05543311 0.03727069 0.05543311 0.07622154 0.06776469 0.03167950 12 0.28875806 0.04642960 0.07622154 0.04642960 0.04794192 0.03727069 0.06776469 13 0.05840222 0.18241379 0.04794192 0.25976771 0.07622154 0.03167950 0.03727069 14 0.06776469 1.21769038 0.07622154 0.28875806 0.04794192 0.06776469 0.04642960 15 0.03727069 0.28875806 0.03727069 0.03727069 0.06776469 0.03727069 0.04435191 16 0.04794192 0.04642960 0.04557920 0.04557920 0.06776469 0.28875806 0.06776469 17 0.07622154 0.06776469 0.03167950 0.07622154 0.03727069 0.05840222 0.03727069 18 0.04794192 0.04642960 0.03727069 0.04435191 0.07622154 0.03167950 0.03727069 19 0.04794192 0.04435191 0.03167950 0.05543311 0.04794192 0.06776469 0.04642960 ebitda_t4 1 0.04642960 2 0.04435191 3 0.05543311 4 0.04642960 5 0.18241379 6 0.25976771 7 0.04794192 8 0.07622154 9 0.04794192 10 0.04557920 11 0.07622154 12 0.04794192 13 0.04557920 14 0.03167950 15 0.03167950 16 0.65373713 17 0.18241379 18 0.04557920 19 0.03167950 Thanks four your help... Sincerely, Max - M a x i m i l i a n M ue l l e r PhD-Student Department of Business Studies Leuphana Universität Lüneburg -- View this message in context: http://r.789695.n4.nabble.com/Getting-Sphericity-Tests-for-Within-Subject-Repeated-Measure-Anova-using-car-package-tp841030p4259642.html Sent from the R help mailing list archive at Nabble.com. __ R-help@r-project.org 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.
Re: [R] Getting Sphericity Tests for Within Subject Repeated Measure Anova (using car package)
Check out the reshape package for transforming data from long to wide
and vice versa.
Yet I still don't know what problem you've encountered with ezANOVA.
Using the data you just sent, where Day now has 3 levels, I reformat
back to the presumably original long format and find that ezANOVA
returns the same sphericity tests as John's solution (which is
expected because ezANOVA is a wrapper to Anova):
library(ez)
a = read.table( 'Sergios_wide_data.txt' , header=T )
b = melt.data.frame( data=a , id.vars=c('subject','treatment') ,
variable_name='day' )
ezANOVA( data=b , dv=.(value) , sid=.(subject) , within=.(treatment,day) )
On Mon, Nov 9, 2009 at 10:20 PM, Sergios (Sergey) Charntikov
sergios...@gmail.com wrote:
Thank you very much. Finally got it to work. However, I had to recode it
from:
columns: subject/treatment/DV (where all my response data was in one
DV column) to columns: subject/treatment/day1/day2/day3/ (where my
response data is now in three different columns).
Is there a way to do that without hand recoding (cutting and pasting
in spreadsheet) by hand? Thank you for your help. Glad it works as
is.
Sincerely,
Sergios Charntikov (Sergey), MA
Behavioral Neuropharmacology Lab
Department of Psychology
University of Nebraska-Lincoln
Lincoln, NE 68588-0308 USA
On Mon, Nov 9, 2009 at 7:12 PM, John Fox j...@mcmaster.ca wrote:
Dear Sergios,
Why don't you try what I suggested originally? Adapted to this data set,
mod - lm(cbind(day1, day2, day3) ~ Treatment, data=Dataset)
idata - data.frame(Day=factor(1:3))
summary(Anova(mod, idata=idata, idesign=~Day))
Peter Dalgaard also pointed toward an article that describes how to do the
same thing with anova().
Regards,
John
-Original Message-
From: r-help-boun...@r-project.org [mailto:r-help-boun...@r-project.org]
On
Behalf Of Sergios (Sergey) Charntikov
Sent: November-09-09 7:13 PM
To: Mike Lawrence
Cc: r-help@r-project.org
Subject: Re: [R] Getting Sphericity Tests for Within Subject Repeated
Measure
Anova (using car package)
Hi Mike,
I tried to run my data in SPSS and it works fine without any problems,
plug
in my levels, plug in my covariate (since it is all within) and get my
Mauchly Tests.
I tried to rearrange the data so it looks like this
subj/treatment/day1/day2/day3
subject treatment day1 day2 day3
1 1 8 8 8
1 2 5 7 5
2 1 7 4 4
2 2 4 5 7
3 1 8 6 4
3 2 5 2 4
4 1 2 9 4
4 2 1 9 1
5 1 4 8 1
5 2 7 8 2
6 1 4 7 2
6 2 4 5 2
When I try mlmfit - lm(Dataset~1), I get invalid type (list) for
variable
'Dataset
When I try
mod - lm(cbind(day1, day2, day3) ~ Treatment, data=Dataset)
idata- data.frame(factor(rep(c(Dataset$day1, Dataset$day2,
Dataset$day3))),
ordered(Dataset$Treatment))
Anova(mod, idata=idata, idesign=~Dataset$Treatment)
I get: Terms in the intra-subject model matrix are not orthogonal.
When I try is.matrix(Dataset) - I get no.
My original mock Dataset (attached in txt) is below. Maybe I am not
coding
it right? I would hate to recode all my data for SPSS, since at the end I
would need to show that Sphericity was not violated.
Subj Trtmt Sessn Response
1 N 1 5
1 D 1 6
1 N 2 4
1 D 2 7
2 N 1 8
2 D 1 9
2 N 2 2
2 D 2 1
3 N 1 4
3 D 1 5
3 N 2 6
3 D 2 2
4 N 1 5
4 D 1 6
4 N 2 4
4 D 2 7
5 N 1 8
5 D 1 9
5 N 2 2
5 D 2 1
6 N 1 4
6 D 1 5
6 N 2 6
6 D 2 2
Sincerely,
Sergios Charntikov (Sergey), MA
Behavioral Neuropharmacology Lab
Department of Psychology
University of Nebraska-Lincoln
Lincoln, NE 68588-0308 USA
On Mon, Nov 9, 2009 at 5:29 PM, Mike Lawrence mike.lawre...@dal.ca
wrote:
No luck as in...? What error did you encounter?
In your example data set, you only have 2 levels of each within-Ss
factor, in which case you shouldn't expect to obtain tests of
sphericity; as far as I understand it, sphericity necessarily holds
when for repeated measures with only 2 levels and tests are really
only possible for repeated measures with 3 or more levels.
I think it's analogous to how you don't need to test homogeneity of
variance when performing a paired t-test; the test ends up
representing the pairs as single distribution of difference scores
with a single variance.
Mike
On Mon, Nov 9, 2009 at 5:30 PM, Sergios (Sergey) Charntikov
sergios...@gmail.com wrote:
Tried EZanova, no luck with my particular dataset
Re: [R] Getting Sphericity Tests for Within Subject Repeated Measure Anova (using car package)
Oops, I see now that despite repeated subject names, treatment is a
between-Ss variable, so you need to use this to get the equivalent of
Anova:
library(ez)
a = read.table( 'Sergios_wide_data.txt' , header=T )
b = melt.data.frame( data=a , id.vars=c('subject','treatment') ,
variable_name='day' )
b$subject=paste(b$subject,b$treatment) #create unique sids
ezANOVA( data=b , dv=.(value) , sid=.(subject) , within=.(day) ,
between=.(treatment) )
On Tue, Nov 10, 2009 at 6:47 AM, Mike Lawrence mike.lawre...@dal.ca wrote:
Check out the reshape package for transforming data from long to wide
and vice versa.
Yet I still don't know what problem you've encountered with ezANOVA.
Using the data you just sent, where Day now has 3 levels, I reformat
back to the presumably original long format and find that ezANOVA
returns the same sphericity tests as John's solution (which is
expected because ezANOVA is a wrapper to Anova):
library(ez)
a = read.table( 'Sergios_wide_data.txt' , header=T )
b = melt.data.frame( data=a , id.vars=c('subject','treatment') ,
variable_name='day' )
ezANOVA( data=b , dv=.(value) , sid=.(subject) , within=.(treatment,day) )
On Mon, Nov 9, 2009 at 10:20 PM, Sergios (Sergey) Charntikov
sergios...@gmail.com wrote:
Thank you very much. Finally got it to work. However, I had to recode it
from:
columns: subject/treatment/DV (where all my response data was in one
DV column) to columns: subject/treatment/day1/day2/day3/ (where my
response data is now in three different columns).
Is there a way to do that without hand recoding (cutting and pasting
in spreadsheet) by hand? Thank you for your help. Glad it works as
is.
Sincerely,
Sergios Charntikov (Sergey), MA
Behavioral Neuropharmacology Lab
Department of Psychology
University of Nebraska-Lincoln
Lincoln, NE 68588-0308 USA
On Mon, Nov 9, 2009 at 7:12 PM, John Fox j...@mcmaster.ca wrote:
Dear Sergios,
Why don't you try what I suggested originally? Adapted to this data set,
mod - lm(cbind(day1, day2, day3) ~ Treatment, data=Dataset)
idata - data.frame(Day=factor(1:3))
summary(Anova(mod, idata=idata, idesign=~Day))
Peter Dalgaard also pointed toward an article that describes how to do the
same thing with anova().
Regards,
John
-Original Message-
From: r-help-boun...@r-project.org [mailto:r-help-boun...@r-project.org]
On
Behalf Of Sergios (Sergey) Charntikov
Sent: November-09-09 7:13 PM
To: Mike Lawrence
Cc: r-help@r-project.org
Subject: Re: [R] Getting Sphericity Tests for Within Subject Repeated
Measure
Anova (using car package)
Hi Mike,
I tried to run my data in SPSS and it works fine without any problems,
plug
in my levels, plug in my covariate (since it is all within) and get my
Mauchly Tests.
I tried to rearrange the data so it looks like this
subj/treatment/day1/day2/day3
subject treatment day1 day2 day3
1 1 8 8 8
1 2 5 7 5
2 1 7 4 4
2 2 4 5 7
3 1 8 6 4
3 2 5 2 4
4 1 2 9 4
4 2 1 9 1
5 1 4 8 1
5 2 7 8 2
6 1 4 7 2
6 2 4 5 2
When I try mlmfit - lm(Dataset~1), I get invalid type (list) for
variable
'Dataset
When I try
mod - lm(cbind(day1, day2, day3) ~ Treatment, data=Dataset)
idata- data.frame(factor(rep(c(Dataset$day1, Dataset$day2,
Dataset$day3))),
ordered(Dataset$Treatment))
Anova(mod, idata=idata, idesign=~Dataset$Treatment)
I get: Terms in the intra-subject model matrix are not orthogonal.
When I try is.matrix(Dataset) - I get no.
My original mock Dataset (attached in txt) is below. Maybe I am not
coding
it right? I would hate to recode all my data for SPSS, since at the end I
would need to show that Sphericity was not violated.
Subj Trtmt Sessn Response
1 N 1 5
1 D 1 6
1 N 2 4
1 D 2 7
2 N 1 8
2 D 1 9
2 N 2 2
2 D 2 1
3 N 1 4
3 D 1 5
3 N 2 6
3 D 2 2
4 N 1 5
4 D 1 6
4 N 2 4
4 D 2 7
5 N 1 8
5 D 1 9
5 N 2 2
5 D 2 1
6 N 1 4
6 D 1 5
6 N 2 6
6 D 2 2
Sincerely,
Sergios Charntikov (Sergey), MA
Behavioral Neuropharmacology Lab
Department of Psychology
University of Nebraska-Lincoln
Lincoln, NE 68588-0308 USA
On Mon, Nov 9, 2009 at 5:29 PM, Mike Lawrence mike.lawre...@dal.ca
wrote:
No luck as in...? What error did you encounter?
In your example data set, you only have 2 levels of each within-Ss
factor, in which case you shouldn't expect to obtain tests of
sphericity; as far as I understand it, sphericity necessarily
Re: [R] Getting Sphericity Tests for Within Subject Repeated Measure Anova (using car package)
Thank you. I think that this is what I was looking for. I am getting
the hang of it with my data. Thank you all.
Sincerely,
Sergios Charntikov (Sergey), MA
Behavioral Neuropharmacology Lab
Department of Psychology
University of Nebraska-Lincoln
Lincoln, NE 68588-0308 USA
On Tue, Nov 10, 2009 at 6:14 AM, Mike Lawrence mike.lawre...@dal.ca wrote:
Oops, I see now that despite repeated subject names, treatment is a
between-Ss variable, so you need to use this to get the equivalent of
Anova:
library(ez)
a = read.table( 'Sergios_wide_data.txt' , header=T )
b = melt.data.frame( data=a , id.vars=c('subject','treatment') ,
variable_name='day' )
b$subject=paste(b$subject,b$treatment) #create unique sids
ezANOVA( data=b , dv=.(value) , sid=.(subject) , within=.(day) ,
between=.(treatment) )
On Tue, Nov 10, 2009 at 6:47 AM, Mike Lawrence mike.lawre...@dal.ca wrote:
Check out the reshape package for transforming data from long to wide
and vice versa.
Yet I still don't know what problem you've encountered with ezANOVA.
Using the data you just sent, where Day now has 3 levels, I reformat
back to the presumably original long format and find that ezANOVA
returns the same sphericity tests as John's solution (which is
expected because ezANOVA is a wrapper to Anova):
library(ez)
a = read.table( 'Sergios_wide_data.txt' , header=T )
b = melt.data.frame( data=a , id.vars=c('subject','treatment') ,
variable_name='day' )
ezANOVA( data=b , dv=.(value) , sid=.(subject) , within=.(treatment,day) )
On Mon, Nov 9, 2009 at 10:20 PM, Sergios (Sergey) Charntikov
sergios...@gmail.com wrote:
Thank you very much. Finally got it to work. However, I had to recode it
from:
columns: subject/treatment/DV (where all my response data was in one
DV column) to columns: subject/treatment/day1/day2/day3/ (where my
response data is now in three different columns).
Is there a way to do that without hand recoding (cutting and pasting
in spreadsheet) by hand? Thank you for your help. Glad it works as
is.
Sincerely,
Sergios Charntikov (Sergey), MA
Behavioral Neuropharmacology Lab
Department of Psychology
University of Nebraska-Lincoln
Lincoln, NE 68588-0308 USA
On Mon, Nov 9, 2009 at 7:12 PM, John Fox j...@mcmaster.ca wrote:
Dear Sergios,
Why don't you try what I suggested originally? Adapted to this data set,
mod - lm(cbind(day1, day2, day3) ~ Treatment, data=Dataset)
idata - data.frame(Day=factor(1:3))
summary(Anova(mod, idata=idata, idesign=~Day))
Peter Dalgaard also pointed toward an article that describes how to do the
same thing with anova().
Regards,
John
-Original Message-
From: r-help-boun...@r-project.org [mailto:r-help-boun...@r-project.org]
On
Behalf Of Sergios (Sergey) Charntikov
Sent: November-09-09 7:13 PM
To: Mike Lawrence
Cc: r-help@r-project.org
Subject: Re: [R] Getting Sphericity Tests for Within Subject Repeated
Measure
Anova (using car package)
Hi Mike,
I tried to run my data in SPSS and it works fine without any problems,
plug
in my levels, plug in my covariate (since it is all within) and get my
Mauchly Tests.
I tried to rearrange the data so it looks like this
subj/treatment/day1/day2/day3
subject treatment day1 day2 day3
1 1 8 8 8
1 2 5 7 5
2 1 7 4 4
2 2 4 5 7
3 1 8 6 4
3 2 5 2 4
4 1 2 9 4
4 2 1 9 1
5 1 4 8 1
5 2 7 8 2
6 1 4 7 2
6 2 4 5 2
When I try mlmfit - lm(Dataset~1), I get invalid type (list) for
variable
'Dataset
When I try
mod - lm(cbind(day1, day2, day3) ~ Treatment, data=Dataset)
idata- data.frame(factor(rep(c(Dataset$day1, Dataset$day2,
Dataset$day3))),
ordered(Dataset$Treatment))
Anova(mod, idata=idata, idesign=~Dataset$Treatment)
I get: Terms in the intra-subject model matrix are not orthogonal.
When I try is.matrix(Dataset) - I get no.
My original mock Dataset (attached in txt) is below. Maybe I am not
coding
it right? I would hate to recode all my data for SPSS, since at the end I
would need to show that Sphericity was not violated.
Subj Trtmt Sessn Response
1 N 1 5
1 D 1 6
1 N 2 4
1 D 2 7
2 N 1 8
2 D 1 9
2 N 2 2
2 D 2 1
3 N 1 4
3 D 1 5
3 N 2 6
3 D 2 2
4 N 1 5
4 D 1 6
4 N 2 4
4 D 2 7
5 N 1 8
5 D 1 9
5 N 2 2
5 D 2 1
6 N 1 4
6 D 1 5
6 N 2 6
6 D 2 2
Sincerely,
Sergios Charntikov (Sergey), MA
Behavioral Neuropharmacology Lab
Department of Psychology
University
Re: [R] Getting Sphericity Tests for Within Subject Repeated Measure Anova (using car package) (Adjusted Dataset)
Dear Segios, For repeated-measures designs, the Anova() function requires a multivariate linear model fit to the wide version of the data set, in which each of the repeated measures appears as a separate variable. It is necessary that you have the same occasions observed for all subjects. For your scaled-down example, you'd have two response variables named, e.g., Sessn1 and Sessn2. Then you'd fit the multivariate linear model as mod - lm(cbind(Sessn1, Sessn2) ~ Trtmnt, data=Dataset). The idata data frame could simply be idata - data.frame(Sessn=factor(1:2)). Then you could get the MANOVA and repeated-measure ANOVA, including sphericity test, etc., as summary(Anova(mod, idata=idata, idesign=~Sessn)). I hope this helps, John John Fox Senator William McMaster Professor of Social Statistics Department of Sociology McMaster University Hamilton, Ontario, Canada web: socserv.mcmaster.ca/jfox -Original Message- From: r-help-boun...@r-project.org [mailto:r-help-boun...@r-project.org] On Behalf Of Sergios (Sergey) Charntikov Sent: November-09-09 1:18 PM To: r-help@r-project.org Subject: [R] 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 that I am not getting something right. Dataset$Sessn - as.factor(Dataset$Sessn) LinearModel.1 - lm(Response ~ Sessn*Trtmt, data=Dataset) summary(LinearModel.1) All, good so far, but I have problem understanding idata= and idesign= functions pertaining to my example. Session is my repeated measure (Sessn 1 and Sessn 2 = two sessions, in reality I have more) and it is already stacked. Any help or guidance on this matter. Thank you, my mock dataset is below. Each subject has two levels of treatment throughout four calendar days which are recoded to Session 1 and Session 2 in order to compare treatments by the first and subsequent days of exposure (Treatment x Session; my DV is Response; Session is repeated). Subj Trtmt Sessn Response 1 N 1 5 1 D 1 6 1 N 2 4 1 D 2 7 2 N 1 8 2 D 1 9 2 N 2 2 2 D 2 1 3 N 1 4 3 D 1 5 3 N 2 6 3 D 2 2 4 N 1 5 4 D 1 6 4 N 2 4 4 D 2 7 5 N 1 8 5 D 1 9 5 N 2 2 5 D 2 1 6 N 1 4 6 D 1 5 6 N 2 6 6 D 2 2 Sincerely, Sergios Charntikov (Sergey), MA Behavioral Neuropharmacology Lab Department of Psychology University of Nebraska-Lincoln Lincoln, NE 68588-0308 USA sergioschr-at-gmail-dot-com [[alternative HTML version deleted]] __ R-help@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code. __ R-help@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.
Re: [R] Getting Sphericity Tests for Within Subject Repeated Measure Anova (using car package) (Adjusted Dataset)
Based on what you suggested I did the following: 1. Dataset$Sessn - as.factor(Dataset$Sessn) 2. mod - lm(cbind(Sessn==1, Sessn==2) ~ Trtmt, data=Dataset) 3. idata - data.frame(Sessn=factor(1:2)) 4. Anova(mod, idata=idata, idesign=~Sessn)) ERROR: The error SSP matrix is apparently of deficient rank = 0 1 I have noticed that my DV (Response) is not in play in the coding above. Then I have modified it to: mod2 - lm(*Response*~(cbind(Sessn==1, Sessn==2)) * Trtmt, data=Dataset) idata2 - data.frame(Sessn=factor(1:2)) Anova(mod, idata=idata2, idesign=~Sessn) ERROR: The error SSP matrix is apparently of deficient rank = 0 1 Then I have modified it to: mod2 - lm(Response~(cbind(Sessn==1, Sessn==2)) * Trtmt, data=Dataset) idata2 - data.frame(Sessn=factor(1:2)) Anova(mod, idata=idata2, idesign=~*(cbind(Sessn==1, Sessn==2)) * Trtmt*) ERROR: object 'Trtmt' not found Then I have modified it to: mod2 - lm(Response~(cbind(Sessn==1, Sessn==2)) * Trtmt, data=Dataset) idata2 - data.frame(Sessn=factor(1:2)) Anova(mod, idata=idata2, idesign=~(cbind(Sessn==1, Sessn==2)) * * Dataset$Trtmt*) ERROR: variable lengths differ (found for 'Dataset$Trtmt') [THIS IS THE ERROR THAT I HAVE BEEN GETTING WITH MY ACTUAL DATASET FOLLOWING CAR PACKAGE RECOMMENDATIONS) Any idea what am I doing wrong? I have attached my mock data for convenience in csv. Sincerely, Sergios Charntikov (Sergey), MA Behavioral Neuropharmacology Lab Department of Psychology University of Nebraska-Lincoln Lincoln, NE 68588-0308 USA sergios...@gmail.com www.unl.edu/psychoneuropharm/ On Mon, Nov 9, 2009 at 12:33 PM, John Fox j...@mcmaster.ca wrote: Dear Segios, For repeated-measures designs, the Anova() function requires a multivariate linear model fit to the wide version of the data set, in which each of the repeated measures appears as a separate variable. It is necessary that you have the same occasions observed for all subjects. For your scaled-down example, you'd have two response variables named, e.g., Sessn1 and Sessn2. Then you'd fit the multivariate linear model as mod - lm(cbind(Sessn1, Sessn2) ~ Trtmnt, data=Dataset). The idata data frame could simply be idata - data.frame(Sessn=factor(1:2)). Then you could get the MANOVA and repeated-measure ANOVA, including sphericity test, etc., as summary(Anova(mod, idata=idata, idesign=~Sessn)). I hope this helps, John John Fox Senator William McMaster Professor of Social Statistics Department of Sociology McMaster University Hamilton, Ontario, Canada web: socserv.mcmaster.ca/jfox -Original Message- From: r-help-boun...@r-project.org [mailto:r-help-boun...@r-project.org] On Behalf Of Sergios (Sergey) Charntikov Sent: November-09-09 1:18 PM To: r-help@r-project.org Subject: [R] 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 that I am not getting something right. Dataset$Sessn - as.factor(Dataset$Sessn) LinearModel.1 - lm(Response ~ Sessn*Trtmt, data=Dataset) summary(LinearModel.1) All, good so far, but I have problem understanding idata= and idesign= functions pertaining to my example. Session is my repeated measure (Sessn 1 and Sessn 2 = two sessions, in reality I have more) and it is already stacked. Any help or guidance on this matter. Thank you, my mock dataset is below. Each subject has two levels of treatment throughout four calendar days which are recoded to Session 1 and Session 2 in order to compare treatments by the first and subsequent days of exposure (Treatment x Session; my DV is Response; Session is repeated). Subj Trtmt Sessn Response 1 N 1 5 1 D 1 6 1 N 2 4 1 D 2 7 2 N 1 8 2 D 1 9 2 N 2 2 2 D 2 1 3 N 1 4 3 D 1 5 3 N 2 6 3 D 2 2 4 N 1 5 4 D 1 6 4 N 2 4 4 D 2 7 5 N 1 8 5 D 1 9 5 N 2 2 5 D 2 1 6 N 1 4 6 D 1 5 6 N 2 6 6 D 2 2 Sincerely, Sergios Charntikov (Sergey), MA Behavioral Neuropharmacology Lab Department of Psychology University of Nebraska-Lincoln Lincoln, NE 68588-0308 USA sergioschr-at-gmail-dot-com [[alternative HTML version deleted]] __
Re: [R] Getting Sphericity Tests for Within Subject Repeated Measure Anova (using car package)
Have you tried ezANOVA from the ez pacakge? It attempts to provide a simple user interface to car's ANOVA (and when that fails, aov). On Mon, Nov 9, 2009 at 1:44 PM, Sergios (Sergey) Charntikov sergios...@gmail.com wrote: Hello everyone, I am trying to do within subjects repeated measures anova followed by the test of sphericity (sample dataset below). I am able to get either mixed model or linear model anova and TukeyHSD, but have no luck with Repeated-Measures Assuming Sphericity or Separate Sphericity Tests. I am trying to follow example from car package, but it seems that I am not getting something right. Dataset$Sessn - as.factor(Dataset$Sessn) LinearModel.1 - lm(Response ~ Sessn*Trtmt, data=Dataset) summary(LinearModel.1) All, good so far, but I have problem understanding idata= and idesign= functions pertaining to my example. Session is my repeated measure (Sessn 1 and Sessn 2 = two sessions, in reality I have more) and it is already stacked. Any help or guidance on this matter. Thank you, my mock dataset is below. Each subject has two levels of treatment throughout four calendar days which are recoded to Session 1 and Session 2 in order to compare treatments by the first and subsequent days of exposure (Treatment x Session; my DV is Response; Session is repeated). Subj Trtmt Sessn Response 1 N 1 5 1 D 1 6 1 N 2 4 1 D 2 7 2 N 1 8 2 D 1 9 2 N 2 2 2 D 2 1 3 N 1 4 3 D 1 5 3 N 2 6 3 D 2 2 4 N 1 5 4 D 1 6 4 N 2 4 4 D 2 7 5 N 1 8 5 D 1 9 5 N 2 2 5 D 2 1 6 N 1 4 6 D 1 5 6 N 2 6 6 D 2 2 Sincerely, Sergios Charntikov (Sergey), MA Behavioral Neuropharmacology Lab Department of Psychology University of Nebraska-Lincoln Lincoln, NE 68588-0308 USA sergioschr-at-gmail-dot-com [[alternative HTML version deleted]] __ R-help@r-project.org 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. -- Mike Lawrence Graduate Student Department of Psychology Dalhousie University Looking to arrange a meeting? Check my public calendar: http://tr.im/mikes_public_calendar ~ Certainty is folly... I think. ~ __ R-help@r-project.org 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.
Re: [R] Getting Sphericity Tests for Within Subject Repeated Measure Anova (using car package)
Tried EZanova, no luck with my particular dataset. Sincerely, Sergios Charntikov (Sergey), MA Behavioral Neuropharmacology Lab Department of Psychology University of Nebraska-Lincoln Lincoln, NE 68588-0308 USA On Mon, Nov 9, 2009 at 2:25 PM, Mike Lawrence mike.lawre...@dal.ca wrote: Have you tried ezANOVA from the ez pacakge? It attempts to provide a simple user interface to car's ANOVA (and when that fails, aov). On Mon, Nov 9, 2009 at 1:44 PM, Sergios (Sergey) Charntikov sergios...@gmail.com wrote: 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 right. Dataset$Sessn - as.factor(Dataset$Sessn) LinearModel.1 - lm(Response ~ Sessn*Trtmt, data=Dataset) summary(LinearModel.1) All, good so far, but I have problem understanding idata= and idesign= functions pertaining to my example. Session is my repeated measure (Sessn 1 and Sessn 2 = two sessions, in reality I have more) and it is already stacked. Any help or guidance on this matter. Thank you, my mock dataset is below. Each subject has two levels of treatment throughout four calendar days which are recoded to Session 1 and Session 2 in order to compare treatments by the first and subsequent days of exposure (Treatment x Session; my DV is Response; Session is repeated). Subj Trtmt Sessn Response 1 N 1 5 1 D 1 6 1 N 2 4 1 D 2 7 2 N 1 8 2 D 1 9 2 N 2 2 2 D 2 1 3 N 1 4 3 D 1 5 3 N 2 6 3 D 2 2 4 N 1 5 4 D 1 6 4 N 2 4 4 D 2 7 5 N 1 8 5 D 1 9 5 N 2 2 5 D 2 1 6 N 1 4 6 D 1 5 6 N 2 6 6 D 2 2 Sincerely, Sergios Charntikov (Sergey), MA Behavioral Neuropharmacology Lab Department of Psychology University of Nebraska-Lincoln Lincoln, NE 68588-0308 USA sergioschr-at-gmail-dot-com [[alternative HTML version deleted]] __ R-help@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code. -- Mike Lawrence Graduate Student Department of Psychology Dalhousie University Looking to arrange a meeting? Check my public calendar: http://tr.im/mikes_public_calendar ~ Certainty is folly... I think. ~ [[alternative HTML version deleted]] __ R-help@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.
Re: [R] Getting Sphericity Tests for Within Subject Repeated Measure Anova (using car package) (Adjusted Dataset)
Sergios (Sergey) Charntikov wrote: Based on what you suggested I did the following: 1. Dataset$Sessn - as.factor(Dataset$Sessn) 2. mod - lm(cbind(Sessn==1, Sessn==2) ~ Trtmt, data=Dataset) 3. idata - data.frame(Sessn=factor(1:2)) 4. Anova(mod, idata=idata, idesign=~Sessn)) ERROR: The error SSP matrix is apparently of deficient rank = 0 1 I have noticed that my DV (Response) is not in play in the coding above. Then I have modified it to: mod2 - lm(*Response*~(cbind(Sessn==1, Sessn==2)) * Trtmt, data=Dataset) idata2 - data.frame(Sessn=factor(1:2)) Anova(mod, idata=idata2, idesign=~Sessn) ERROR: The error SSP matrix is apparently of deficient rank = 0 1 Then I have modified it to: mod2 - lm(Response~(cbind(Sessn==1, Sessn==2)) * Trtmt, data=Dataset) idata2 - data.frame(Sessn=factor(1:2)) Anova(mod, idata=idata2, idesign=~*(cbind(Sessn==1, Sessn==2)) * Trtmt*) ERROR: object 'Trtmt' not found Then I have modified it to: mod2 - lm(Response~(cbind(Sessn==1, Sessn==2)) * Trtmt, data=Dataset) idata2 - data.frame(Sessn=factor(1:2)) Anova(mod, idata=idata2, idesign=~(cbind(Sessn==1, Sessn==2)) * * Dataset$Trtmt*) ERROR: variable lengths differ (found for 'Dataset$Trtmt') [THIS IS THE ERROR THAT I HAVE BEEN GETTING WITH MY ACTUAL DATASET FOLLOWING CAR PACKAGE RECOMMENDATIONS) Any idea what am I doing wrong? I have attached my mock data for convenience in csv. Either you forgot, or your mailer did not say that it is a text file, and the mailing list software consequently scrubbed it... I think what you need is an analysis of 6 observations with a 2x2==4-dimensional response. You may want to look at my paper in R News 2007-2. The reacttime example used there is pretty similar. You're not going to get much sphericity testing when all factors have only two levels, though. Sincerely, Sergios Charntikov (Sergey), MA Behavioral Neuropharmacology Lab Department of Psychology University of Nebraska-Lincoln Lincoln, NE 68588-0308 USA sergios...@gmail.com www.unl.edu/psychoneuropharm/ On Mon, Nov 9, 2009 at 12:33 PM, John Fox j...@mcmaster.ca wrote: Dear Segios, For repeated-measures designs, the Anova() function requires a multivariate linear model fit to the wide version of the data set, in which each of the repeated measures appears as a separate variable. It is necessary that you have the same occasions observed for all subjects. For your scaled-down example, you'd have two response variables named, e.g., Sessn1 and Sessn2. Then you'd fit the multivariate linear model as mod - lm(cbind(Sessn1, Sessn2) ~ Trtmnt, data=Dataset). The idata data frame could simply be idata - data.frame(Sessn=factor(1:2)). Then you could get the MANOVA and repeated-measure ANOVA, including sphericity test, etc., as summary(Anova(mod, idata=idata, idesign=~Sessn)). I hope this helps, John John Fox Senator William McMaster Professor of Social Statistics Department of Sociology McMaster University Hamilton, Ontario, Canada web: socserv.mcmaster.ca/jfox -Original Message- From: r-help-boun...@r-project.org [mailto:r-help-boun...@r-project.org] On Behalf Of Sergios (Sergey) Charntikov Sent: November-09-09 1:18 PM To: r-help@r-project.org Subject: [R] 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 that I am not getting something right. Dataset$Sessn - as.factor(Dataset$Sessn) LinearModel.1 - lm(Response ~ Sessn*Trtmt, data=Dataset) summary(LinearModel.1) All, good so far, but I have problem understanding idata= and idesign= functions pertaining to my example. Session is my repeated measure (Sessn 1 and Sessn 2 = two sessions, in reality I have more) and it is already stacked. Any help or guidance on this matter. Thank you, my mock dataset is below. Each subject has two levels of treatment throughout four calendar days which are recoded to Session 1 and Session 2 in order to compare treatments by the first and subsequent days of exposure (Treatment x Session; my DV is Response; Session is repeated). Subj Trtmt Sessn Response 1 N 1 5 1 D 1 6 1 N 2 4 1 D 2 7 2 N 1 8 2 D 1 9 2 N 2 2 2 D 2 1 3 N 1 4 3 D 1 5 3 N 2 6 3 D 2 2 4 N 1 5 4 D 1 6 4 N 2 4 4 D 2 7 5 N 1 8 5 D 1 9 5 N 2 2 5 D 2 1 6 N 1 4 6 D 1 5 6 N 2 6 6 D 2
Re: [R] Getting Sphericity Tests for Within Subject Repeated Measure Anova (using car package)
No luck as in...? What error did you encounter? In your example data set, you only have 2 levels of each within-Ss factor, in which case you shouldn't expect to obtain tests of sphericity; as far as I understand it, sphericity necessarily holds when for repeated measures with only 2 levels and tests are really only possible for repeated measures with 3 or more levels. I think it's analogous to how you don't need to test homogeneity of variance when performing a paired t-test; the test ends up representing the pairs as single distribution of difference scores with a single variance. Mike On Mon, Nov 9, 2009 at 5:30 PM, Sergios (Sergey) Charntikov sergios...@gmail.com wrote: Tried EZanova, no luck with my particular dataset. Sincerely, Sergios Charntikov (Sergey), MA Behavioral Neuropharmacology Lab Department of Psychology University of Nebraska-Lincoln Lincoln, NE 68588-0308 USA On Mon, Nov 9, 2009 at 2:25 PM, Mike Lawrence mike.lawre...@dal.ca wrote: Have you tried ezANOVA from the ez pacakge? It attempts to provide a simple user interface to car's ANOVA (and when that fails, aov). On Mon, Nov 9, 2009 at 1:44 PM, Sergios (Sergey) Charntikov sergios...@gmail.com wrote: 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 right. Dataset$Sessn - as.factor(Dataset$Sessn) LinearModel.1 - lm(Response ~ Sessn*Trtmt, data=Dataset) summary(LinearModel.1) All, good so far, but I have problem understanding idata= and idesign= functions pertaining to my example. Session is my repeated measure (Sessn 1 and Sessn 2 = two sessions, in reality I have more) and it is already stacked. Any help or guidance on this matter. Thank you, my mock dataset is below. Each subject has two levels of treatment throughout four calendar days which are recoded to Session 1 and Session 2 in order to compare treatments by the first and subsequent days of exposure (Treatment x Session; my DV is Response; Session is repeated). Subj Trtmt Sessn Response 1 N 1 5 1 D 1 6 1 N 2 4 1 D 2 7 2 N 1 8 2 D 1 9 2 N 2 2 2 D 2 1 3 N 1 4 3 D 1 5 3 N 2 6 3 D 2 2 4 N 1 5 4 D 1 6 4 N 2 4 4 D 2 7 5 N 1 8 5 D 1 9 5 N 2 2 5 D 2 1 6 N 1 4 6 D 1 5 6 N 2 6 6 D 2 2 Sincerely, Sergios Charntikov (Sergey), MA Behavioral Neuropharmacology Lab Department of Psychology University of Nebraska-Lincoln Lincoln, NE 68588-0308 USA sergioschr-at-gmail-dot-com [[alternative HTML version deleted]] __ R-help@r-project.org 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. -- Mike Lawrence Graduate Student Department of Psychology Dalhousie University Looking to arrange a meeting? Check my public calendar: http://tr.im/mikes_public_calendar ~ Certainty is folly... I think. ~ -- Mike Lawrence Graduate Student Department of Psychology Dalhousie University Looking to arrange a meeting? Check my public calendar: http://tr.im/mikes_public_calendar ~ Certainty is folly... I think. ~ __ R-help@r-project.org 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.
Re: [R] Getting Sphericity Tests for Within Subject Repeated Measure Anova (using car package)
Hi Mike, I tried to run my data in SPSS and it works fine without any problems, plug in my levels, plug in my covariate (since it is all within) and get my Mauchly Tests. I tried to rearrange the data so it looks like this subj/treatment/day1/day2/day3 subject treatment day1 day2 day3 1 1 8 8 8 1 2 5 7 5 2 1 7 4 4 2 2 4 5 7 3 1 8 6 4 3 2 5 2 4 4 1 2 9 4 4 2 1 9 1 5 1 4 8 1 5 2 7 8 2 6 1 4 7 2 6 2 4 5 2 When I try mlmfit - lm(Dataset~1), I get invalid type (list) for variable 'Dataset When I try mod - lm(cbind(day1, day2, day3) ~ Treatment, data=Dataset) idata- data.frame(factor(rep(c(Dataset$day1, Dataset$day2, Dataset$day3))), ordered(Dataset$Treatment)) Anova(mod, idata=idata, idesign=~Dataset$Treatment) I get: Terms in the intra-subject model matrix are not orthogonal. When I try is.matrix(Dataset) - I get no. My original mock Dataset (attached in txt) is below. Maybe I am not coding it right? I would hate to recode all my data for SPSS, since at the end I would need to show that Sphericity was not violated. SubjTrtmt Sessn Response 1 N 1 5 1 D 1 6 1 N 2 4 1 D 2 7 2 N 1 8 2 D 1 9 2 N 2 2 2 D 2 1 3 N 1 4 3 D 1 5 3 N 2 6 3 D 2 2 4 N 1 5 4 D 1 6 4 N 2 4 4 D 2 7 5 N 1 8 5 D 1 9 5 N 2 2 5 D 2 1 6 N 1 4 6 D 1 5 6 N 2 6 6 D 2 2 Sincerely, Sergios Charntikov (Sergey), MA Behavioral Neuropharmacology Lab Department of Psychology University of Nebraska-Lincoln Lincoln, NE 68588-0308 USA On Mon, Nov 9, 2009 at 5:29 PM, Mike Lawrence mike.lawre...@dal.ca wrote: No luck as in...? What error did you encounter? In your example data set, you only have 2 levels of each within-Ss factor, in which case you shouldn't expect to obtain tests of sphericity; as far as I understand it, sphericity necessarily holds when for repeated measures with only 2 levels and tests are really only possible for repeated measures with 3 or more levels. I think it's analogous to how you don't need to test homogeneity of variance when performing a paired t-test; the test ends up representing the pairs as single distribution of difference scores with a single variance. Mike On Mon, Nov 9, 2009 at 5:30 PM, Sergios (Sergey) Charntikov sergios...@gmail.com wrote: Tried EZanova, no luck with my particular dataset. Sincerely, Sergios Charntikov (Sergey), MA Behavioral Neuropharmacology Lab Department of Psychology University of Nebraska-Lincoln Lincoln, NE 68588-0308 USA On Mon, Nov 9, 2009 at 2:25 PM, Mike Lawrence mike.lawre...@dal.ca wrote: Have you tried ezANOVA from the ez pacakge? It attempts to provide a simple user interface to car's ANOVA (and when that fails, aov). On Mon, Nov 9, 2009 at 1:44 PM, Sergios (Sergey) Charntikov sergios...@gmail.com wrote: 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 right. Dataset$Sessn - as.factor(Dataset$Sessn) LinearModel.1 - lm(Response ~ Sessn*Trtmt, data=Dataset) summary(LinearModel.1) All, good so far, but I have problem understanding idata= and idesign= functions pertaining to my example. Session is my repeated measure (Sessn 1 and Sessn 2 = two sessions, in reality I have more) and it is already stacked. Any help or guidance on this matter. Thank you, my mock dataset is below. Each subject has two levels of treatment throughout four calendar days which are recoded to Session 1 and Session 2 in order to compare treatments by the first and subsequent days of exposure (Treatment x Session; my DV is Response; Session is repeated). Subj Trtmt Sessn Response 1 N 1 5 1 D 1 6 1 N 2 4 1 D 2 7 2 N 1 8 2 D 1 9 2 N 2 2 2 D 2 1 3 N 1 4 3 D 1 5 3 N 2 6 3 D 2 2 4 N 1 5 4 D 1 6 4 N 2 4 4 D 2 7 5 N 1 8 5 D 1 9 5 N 2 2 5 D 2 1 6 N 1 4 6 D 1 5 6 N 2 6 6 D 2 2 Sincerely, Sergios Charntikov (Sergey), MA Behavioral Neuropharmacology Lab Department of Psychology University of Nebraska-Lincoln Lincoln, NE 68588-0308 USA
Re: [R] Getting Sphericity Tests for Within Subject Repeated Measure Anova (using car package)
Dear Sergios, Why don't you try what I suggested originally? Adapted to this data set, mod - lm(cbind(day1, day2, day3) ~ Treatment, data=Dataset) idata - data.frame(Day=factor(1:3)) summary(Anova(mod, idata=idata, idesign=~Day)) Peter Dalgaard also pointed toward an article that describes how to do the same thing with anova(). Regards, John -Original Message- From: r-help-boun...@r-project.org [mailto:r-help-boun...@r-project.org] On Behalf Of Sergios (Sergey) Charntikov Sent: November-09-09 7:13 PM To: Mike Lawrence Cc: r-help@r-project.org Subject: Re: [R] Getting Sphericity Tests for Within Subject Repeated Measure Anova (using car package) Hi Mike, I tried to run my data in SPSS and it works fine without any problems, plug in my levels, plug in my covariate (since it is all within) and get my Mauchly Tests. I tried to rearrange the data so it looks like this subj/treatment/day1/day2/day3 subject treatment day1 day2 day3 1 1 8 8 8 1 2 5 7 5 2 1 7 4 4 2 2 4 5 7 3 1 8 6 4 3 2 5 2 4 4 1 2 9 4 4 2 1 9 1 5 1 4 8 1 5 2 7 8 2 6 1 4 7 2 6 2 4 5 2 When I try mlmfit - lm(Dataset~1), I get invalid type (list) for variable 'Dataset When I try mod - lm(cbind(day1, day2, day3) ~ Treatment, data=Dataset) idata- data.frame(factor(rep(c(Dataset$day1, Dataset$day2, Dataset$day3))), ordered(Dataset$Treatment)) Anova(mod, idata=idata, idesign=~Dataset$Treatment) I get: Terms in the intra-subject model matrix are not orthogonal. When I try is.matrix(Dataset) - I get no. My original mock Dataset (attached in txt) is below. Maybe I am not coding it right? I would hate to recode all my data for SPSS, since at the end I would need to show that Sphericity was not violated. Subj Trtmt Sessn Response 1 N 1 5 1 D 1 6 1 N 2 4 1 D 2 7 2 N 1 8 2 D 1 9 2 N 2 2 2 D 2 1 3 N 1 4 3 D 1 5 3 N 2 6 3 D 2 2 4 N 1 5 4 D 1 6 4 N 2 4 4 D 2 7 5 N 1 8 5 D 1 9 5 N 2 2 5 D 2 1 6 N 1 4 6 D 1 5 6 N 2 6 6 D 2 2 Sincerely, Sergios Charntikov (Sergey), MA Behavioral Neuropharmacology Lab Department of Psychology University of Nebraska-Lincoln Lincoln, NE 68588-0308 USA On Mon, Nov 9, 2009 at 5:29 PM, Mike Lawrence mike.lawre...@dal.ca wrote: No luck as in...? What error did you encounter? In your example data set, you only have 2 levels of each within-Ss factor, in which case you shouldn't expect to obtain tests of sphericity; as far as I understand it, sphericity necessarily holds when for repeated measures with only 2 levels and tests are really only possible for repeated measures with 3 or more levels. I think it's analogous to how you don't need to test homogeneity of variance when performing a paired t-test; the test ends up representing the pairs as single distribution of difference scores with a single variance. Mike On Mon, Nov 9, 2009 at 5:30 PM, Sergios (Sergey) Charntikov sergios...@gmail.com wrote: Tried EZanova, no luck with my particular dataset. Sincerely, Sergios Charntikov (Sergey), MA Behavioral Neuropharmacology Lab Department of Psychology University of Nebraska-Lincoln Lincoln, NE 68588-0308 USA On Mon, Nov 9, 2009 at 2:25 PM, Mike Lawrence mike.lawre...@dal.ca wrote: Have you tried ezANOVA from the ez pacakge? It attempts to provide a simple user interface to car's ANOVA (and when that fails, aov). On Mon, Nov 9, 2009 at 1:44 PM, Sergios (Sergey) Charntikov sergios...@gmail.com wrote: 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 right. Dataset$Sessn - as.factor(Dataset$Sessn) LinearModel.1 - lm(Response ~ Sessn*Trtmt, data=Dataset) summary(LinearModel.1) All, good so far, but I have problem understanding idata= and idesign= functions pertaining to my example. Session is my repeated measure (Sessn 1 and Sessn 2 = two sessions, in reality I have more) and it is already stacked. Any help or guidance
Re: [R] Getting Sphericity Tests for Within Subject Repeated Measure Anova (using car package)
Thank you very much. Finally got it to work. However, I had to recode it from: columns: subject/treatment/DV (where all my response data was in one DV column) to columns: subject/treatment/day1/day2/day3/ (where my response data is now in three different columns). Is there a way to do that without hand recoding (cutting and pasting in spreadsheet) by hand? Thank you for your help. Glad it works as is. Sincerely, Sergios Charntikov (Sergey), MA Behavioral Neuropharmacology Lab Department of Psychology University of Nebraska-Lincoln Lincoln, NE 68588-0308 USA On Mon, Nov 9, 2009 at 7:12 PM, John Fox j...@mcmaster.ca wrote: Dear Sergios, Why don't you try what I suggested originally? Adapted to this data set, mod - lm(cbind(day1, day2, day3) ~ Treatment, data=Dataset) idata - data.frame(Day=factor(1:3)) summary(Anova(mod, idata=idata, idesign=~Day)) Peter Dalgaard also pointed toward an article that describes how to do the same thing with anova(). Regards, John -Original Message- From: r-help-boun...@r-project.org [mailto:r-help-boun...@r-project.org] On Behalf Of Sergios (Sergey) Charntikov Sent: November-09-09 7:13 PM To: Mike Lawrence Cc: r-help@r-project.org Subject: Re: [R] Getting Sphericity Tests for Within Subject Repeated Measure Anova (using car package) Hi Mike, I tried to run my data in SPSS and it works fine without any problems, plug in my levels, plug in my covariate (since it is all within) and get my Mauchly Tests. I tried to rearrange the data so it looks like this subj/treatment/day1/day2/day3 subject treatment day1 day2 day3 1 1 8 8 8 1 2 5 7 5 2 1 7 4 4 2 2 4 5 7 3 1 8 6 4 3 2 5 2 4 4 1 2 9 4 4 2 1 9 1 5 1 4 8 1 5 2 7 8 2 6 1 4 7 2 6 2 4 5 2 When I try mlmfit - lm(Dataset~1), I get invalid type (list) for variable 'Dataset When I try mod - lm(cbind(day1, day2, day3) ~ Treatment, data=Dataset) idata- data.frame(factor(rep(c(Dataset$day1, Dataset$day2, Dataset$day3))), ordered(Dataset$Treatment)) Anova(mod, idata=idata, idesign=~Dataset$Treatment) I get: Terms in the intra-subject model matrix are not orthogonal. When I try is.matrix(Dataset) - I get no. My original mock Dataset (attached in txt) is below. Maybe I am not coding it right? I would hate to recode all my data for SPSS, since at the end I would need to show that Sphericity was not violated. Subj Trtmt Sessn Response 1 N 1 5 1 D 1 6 1 N 2 4 1 D 2 7 2 N 1 8 2 D 1 9 2 N 2 2 2 D 2 1 3 N 1 4 3 D 1 5 3 N 2 6 3 D 2 2 4 N 1 5 4 D 1 6 4 N 2 4 4 D 2 7 5 N 1 8 5 D 1 9 5 N 2 2 5 D 2 1 6 N 1 4 6 D 1 5 6 N 2 6 6 D 2 2 Sincerely, Sergios Charntikov (Sergey), MA Behavioral Neuropharmacology Lab Department of Psychology University of Nebraska-Lincoln Lincoln, NE 68588-0308 USA On Mon, Nov 9, 2009 at 5:29 PM, Mike Lawrence mike.lawre...@dal.ca wrote: No luck as in...? What error did you encounter? In your example data set, you only have 2 levels of each within-Ss factor, in which case you shouldn't expect to obtain tests of sphericity; as far as I understand it, sphericity necessarily holds when for repeated measures with only 2 levels and tests are really only possible for repeated measures with 3 or more levels. I think it's analogous to how you don't need to test homogeneity of variance when performing a paired t-test; the test ends up representing the pairs as single distribution of difference scores with a single variance. Mike On Mon, Nov 9, 2009 at 5:30 PM, Sergios (Sergey) Charntikov sergios...@gmail.com wrote: Tried EZanova, no luck with my particular dataset. Sincerely, Sergios Charntikov (Sergey), MA Behavioral Neuropharmacology Lab Department of Psychology University of Nebraska-Lincoln Lincoln, NE 68588-0308 USA On Mon, Nov 9, 2009 at 2:25 PM, Mike Lawrence mike.lawre...@dal.ca wrote: Have you tried ezANOVA from the ez pacakge? It attempts to provide a simple user interface to car's ANOVA (and when that fails, aov). On Mon, Nov 9, 2009 at 1:44 PM, Sergios (Sergey) Charntikov sergios...@gmail.com wrote: 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
Re: [R] Getting Sphericity Tests for Within Subject Repeated Measure Anova (using car package)
Yes, reshaping data is straightforward in R. No need to copy/paste in a spreadsheet. See ?reshape and/or the melt/cast functions in the reshape package. -Ista On Mon, Nov 9, 2009 at 9:20 PM, Sergios (Sergey) Charntikov sergios...@gmail.com wrote: Thank you very much. Finally got it to work. However, I had to recode it from: columns: subject/treatment/DV (where all my response data was in one DV column) to columns: subject/treatment/day1/day2/day3/ (where my response data is now in three different columns). Is there a way to do that without hand recoding (cutting and pasting in spreadsheet) by hand? Thank you for your help. Glad it works as is. Sincerely, Sergios Charntikov (Sergey), MA Behavioral Neuropharmacology Lab Department of Psychology University of Nebraska-Lincoln Lincoln, NE 68588-0308 USA On Mon, Nov 9, 2009 at 7:12 PM, John Fox j...@mcmaster.ca wrote: Dear Sergios, Why don't you try what I suggested originally? Adapted to this data set, mod - lm(cbind(day1, day2, day3) ~ Treatment, data=Dataset) idata - data.frame(Day=factor(1:3)) summary(Anova(mod, idata=idata, idesign=~Day)) Peter Dalgaard also pointed toward an article that describes how to do the same thing with anova(). Regards, John -Original Message- From: r-help-boun...@r-project.org [mailto:r-help-boun...@r-project.org] On Behalf Of Sergios (Sergey) Charntikov Sent: November-09-09 7:13 PM To: Mike Lawrence Cc: r-help@r-project.org Subject: Re: [R] Getting Sphericity Tests for Within Subject Repeated Measure Anova (using car package) Hi Mike, I tried to run my data in SPSS and it works fine without any problems, plug in my levels, plug in my covariate (since it is all within) and get my Mauchly Tests. I tried to rearrange the data so it looks like this subj/treatment/day1/day2/day3 subject treatment day1 day2 day3 1 1 8 8 8 1 2 5 7 5 2 1 7 4 4 2 2 4 5 7 3 1 8 6 4 3 2 5 2 4 4 1 2 9 4 4 2 1 9 1 5 1 4 8 1 5 2 7 8 2 6 1 4 7 2 6 2 4 5 2 When I try mlmfit - lm(Dataset~1), I get invalid type (list) for variable 'Dataset When I try mod - lm(cbind(day1, day2, day3) ~ Treatment, data=Dataset) idata- data.frame(factor(rep(c(Dataset$day1, Dataset$day2, Dataset$day3))), ordered(Dataset$Treatment)) Anova(mod, idata=idata, idesign=~Dataset$Treatment) I get: Terms in the intra-subject model matrix are not orthogonal. When I try is.matrix(Dataset) - I get no. My original mock Dataset (attached in txt) is below. Maybe I am not coding it right? I would hate to recode all my data for SPSS, since at the end I would need to show that Sphericity was not violated. Subj Trtmt Sessn Response 1 N 1 5 1 D 1 6 1 N 2 4 1 D 2 7 2 N 1 8 2 D 1 9 2 N 2 2 2 D 2 1 3 N 1 4 3 D 1 5 3 N 2 6 3 D 2 2 4 N 1 5 4 D 1 6 4 N 2 4 4 D 2 7 5 N 1 8 5 D 1 9 5 N 2 2 5 D 2 1 6 N 1 4 6 D 1 5 6 N 2 6 6 D 2 2 Sincerely, Sergios Charntikov (Sergey), MA Behavioral Neuropharmacology Lab Department of Psychology University of Nebraska-Lincoln Lincoln, NE 68588-0308 USA On Mon, Nov 9, 2009 at 5:29 PM, Mike Lawrence mike.lawre...@dal.ca wrote: No luck as in...? What error did you encounter? In your example data set, you only have 2 levels of each within-Ss factor, in which case you shouldn't expect to obtain tests of sphericity; as far as I understand it, sphericity necessarily holds when for repeated measures with only 2 levels and tests are really only possible for repeated measures with 3 or more levels. I think it's analogous to how you don't need to test homogeneity of variance when performing a paired t-test; the test ends up representing the pairs as single distribution of difference scores with a single variance. Mike On Mon, Nov 9, 2009 at 5:30 PM, Sergios (Sergey) Charntikov sergios...@gmail.com wrote: Tried EZanova, no luck with my particular dataset. Sincerely, Sergios Charntikov (Sergey), MA Behavioral Neuropharmacology Lab Department of Psychology University of Nebraska-Lincoln Lincoln, NE 68588-0308 USA On Mon, Nov 9, 2009 at 2:25 PM, Mike Lawrence mike.lawre...@dal.ca wrote: Have you tried ezANOVA from the ez pacakge? It attempts to provide a simple user interface to car's ANOVA (and when that fails, aov). On Mon, Nov 9, 2009 at 1:44 PM, Sergios (Sergey) Charntikov
Re: [R] Getting Sphericity Tests for Within Subject Repeated Measure Anova (using car package)
Thank you very much for all your help. This helped a lot. Very constructive input. Sincerely, Sergios Charntikov (Sergey), MA Behavioral Neuropharmacology Lab Department of Psychology University of Nebraska-Lincoln Lincoln, NE 68588-0308 USA On Mon, Nov 9, 2009 at 9:53 PM, Ista Zahn istaz...@gmail.com wrote: Yes, reshaping data is straightforward in R. No need to copy/paste in a spreadsheet. See ?reshape and/or the melt/cast functions in the reshape package. -Ista On Mon, Nov 9, 2009 at 9:20 PM, Sergios (Sergey) Charntikov sergios...@gmail.com wrote: Thank you very much. Finally got it to work. However, I had to recode it from: columns: subject/treatment/DV (where all my response data was in one DV column) to columns: subject/treatment/day1/day2/day3/ (where my response data is now in three different columns). Is there a way to do that without hand recoding (cutting and pasting in spreadsheet) by hand? Thank you for your help. Glad it works as is. Sincerely, Sergios Charntikov (Sergey), MA Behavioral Neuropharmacology Lab Department of Psychology University of Nebraska-Lincoln Lincoln, NE 68588-0308 USA On Mon, Nov 9, 2009 at 7:12 PM, John Fox j...@mcmaster.ca wrote: Dear Sergios, Why don't you try what I suggested originally? Adapted to this data set, mod - lm(cbind(day1, day2, day3) ~ Treatment, data=Dataset) idata - data.frame(Day=factor(1:3)) summary(Anova(mod, idata=idata, idesign=~Day)) Peter Dalgaard also pointed toward an article that describes how to do the same thing with anova(). Regards, John -Original Message- From: r-help-boun...@r-project.org [mailto:r-help-boun...@r-project.org] On Behalf Of Sergios (Sergey) Charntikov Sent: November-09-09 7:13 PM To: Mike Lawrence Cc: r-help@r-project.org Subject: Re: [R] Getting Sphericity Tests for Within Subject Repeated Measure Anova (using car package) Hi Mike, I tried to run my data in SPSS and it works fine without any problems, plug in my levels, plug in my covariate (since it is all within) and get my Mauchly Tests. I tried to rearrange the data so it looks like this subj/treatment/day1/day2/day3 subject treatment day1 day2 day3 1 1 8 8 8 1 2 5 7 5 2 1 7 4 4 2 2 4 5 7 3 1 8 6 4 3 2 5 2 4 4 1 2 9 4 4 2 1 9 1 5 1 4 8 1 5 2 7 8 2 6 1 4 7 2 6 2 4 5 2 When I try mlmfit - lm(Dataset~1), I get invalid type (list) for variable 'Dataset When I try mod - lm(cbind(day1, day2, day3) ~ Treatment, data=Dataset) idata- data.frame(factor(rep(c(Dataset$day1, Dataset$day2, Dataset$day3))), ordered(Dataset$Treatment)) Anova(mod, idata=idata, idesign=~Dataset$Treatment) I get: Terms in the intra-subject model matrix are not orthogonal. When I try is.matrix(Dataset) - I get no. My original mock Dataset (attached in txt) is below. Maybe I am not coding it right? I would hate to recode all my data for SPSS, since at the end I would need to show that Sphericity was not violated. Subj Trtmt Sessn Response 1 N 1 5 1 D 1 6 1 N 2 4 1 D 2 7 2 N 1 8 2 D 1 9 2 N 2 2 2 D 2 1 3 N 1 4 3 D 1 5 3 N 2 6 3 D 2 2 4 N 1 5 4 D 1 6 4 N 2 4 4 D 2 7 5 N 1 8 5 D 1 9 5 N 2 2 5 D 2 1 6 N 1 4 6 D 1 5 6 N 2 6 6 D 2 2 Sincerely, Sergios Charntikov (Sergey), MA Behavioral Neuropharmacology Lab Department of Psychology University of Nebraska-Lincoln Lincoln, NE 68588-0308 USA On Mon, Nov 9, 2009 at 5:29 PM, Mike Lawrence mike.lawre...@dal.ca wrote: No luck as in...? What error did you encounter? In your example data set, you only have 2 levels of each within-Ss factor, in which case you shouldn't expect to obtain tests of sphericity; as far as I understand it, sphericity necessarily holds when for repeated measures with only 2 levels and tests are really only possible for repeated measures with 3 or more levels. I think it's analogous to how you don't need to test homogeneity of variance when performing a paired t-test; the test ends up representing the pairs as single distribution of difference scores with a single variance. Mike On Mon, Nov 9, 2009 at 5:30 PM, Sergios (Sergey) Charntikov sergios...@gmail.com wrote: Tried EZanova, no luck with my particular dataset. Sincerely, Sergios Charntikov (Sergey), MA Behavioral Neuropharmacology Lab Department of Psychology University of Nebraska-Lincoln
