Displaying 20 results from an estimated 2000 matches similar to: "Homogeneity of variance tests between more than 2 samples (long)"
2004 Dec 19
1
Different graph type can coexisti??
Please consider a data frame
A B C D
1 4 5 0
2 3 2 75
3 4 1 84
4 5 1 90
5 3 0 100
Is there a way to plot column B and C as barplot *and* D as line on the same
graph??
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2005 Jan 22
0
statistical test improvement of readability (was average disjunction)
Dear all ReadeRs
I was finding a quick method to improve test readability adding or constructing
(with your help....) one or more function that allow what follow.
Please consider
Trt<-c(1,1,1,1,2,2,2,2,3,3,3,3,4,4,4,4,5,5,5,5)
Block<-c(1,2,3,4,1,2,3,4,1,2,3,4,1,2,3,4,1,2,3,4)
AD2DAT<-c(1.44,2.32,1.68,1.28,0.12,0.08,0.24,0.52,0.12,0.08,0.16,0.28,0.16,0.08,0.12,0.12,0.16,0.08,0.32,0.76)
2008 Aug 22
1
Test of Homogeneity of Variances
I am testing the homogeneity of variances via bartlett.test and fligner.test. Using the following example, how should I interpret the p-value in order to accept or reject the null hypothesis ?
set.seed(5)
x <- rnorm(20)
bartlett.test(x, rep(1:5, each=4))
Bartlett test of homogeneity of variances
data: x and rep(1:5, each = 4)
Bartlett's K-squared = 1.7709, df = 4, p-value =
2005 Jul 13
1
Boxcox transformation / homogeneity of variances
Dear r-helpers,
Prior to analysis of variance, I ran the Boxcox function (MASS library) to
find the best power transformation of my data. However, reading the Boxcox
help file, I cannot figure out if this function (through its associated
log-likelihood function) corrects for * normality only * or if it also
induces * homogeneity of variances *. I found in Biometry (Sokal and Rohlf,
p. 419)
2008 Feb 14
5
Levene's test for homogeneity of variances (befor using ANOVA)
En innebygd og tegnsett-uspesifisert tekst ble skilt ut...
Navn: ikke tilgjengelig
Nettadresse: https://stat.ethz.ch/pipermail/r-help/attachments/20080214/5a98c799/attachment.pl
2007 Nov 14
2
Help with Bartlett's test on linear model
Hi all,
I would like to test the homoegeneity of variances between several
linear model for some analysis of covariance. It seems that the
Bartlett's test is a good test to use but I am having problem using with
linear model and I cannot find any examples on the internet. There are
some examples for comparisons of variances but not linear models.
If I take the hellung data set, which is
2010 Mar 21
2
Levene's Test for Homogeneity of Variance
Hi, All!
To calculate Levene's Test for Homogeneity of Variance I use R Commander,
and this is the output:
> levene.test(Dataset$age, Dataset$sex)
Levene's Test for Homogeneity of Variance
Df F value Pr(>F)
group 1 0.8739 0.3567
33
I am not sure what means "Pr(>F)"? Can anyone explain/translate this?
Regards,
Iurie Malai
Department of Psychology and
2003 Nov 01
4
Beginner: Homogenity of Variances
Hello,
for my meta-analysis I try to test if two varainces are equal without
using the raw scores. I have is the SD's, N's and the Means.
I want to test the variances from dependent and independend
samples.
I assume I can use the var.test procedure for the independent
samples, but what about the dependent samples ? Has anyone an
idea how to realise this with R ?
Thanks in advance
2003 Aug 13
4
Levene test of homogeneity of variance
Has the Levene test of homogeneity of variance been implemented in any
library in R?
Thanks,
Maurice Haynes
National Institute of Child Health and Human Development
Child and Family Research Section
6705 Rockledge Drive
Bethesda, MD 20892
Voice: 301-496-8180
Fax: 301-496-2766
E-Mail: mh192j at nih.gov
2005 Jan 25
1
Box-Cox / data transformation question
Dear R users,
Is it reasonable to transform data (measurements of plant height) to the
power of 1/4? I?ve used boxcox(response~A*B) and lambda was close to 0.25.
Regards,
Christoph
2008 Feb 05
2
Incomplete ouput with sink and split=TRUE
Dear List,
I am trying to get R's terminal output to a file and to the terminal
at the same time, so that I can walk through some tests and keep a log
concurrently. The function 'sink' with the option split=TRUE seems to
do just that. It works fine for most output but for objects of class
htest, the terminal output is incomplete (the lines are there but
empty). Here is an
2009 Dec 08
0
Cochran C Test - Homogeneity of Variances
Hi List.
It may be a very simple question, but I couldn’t find an answer on the
internet. Which function (maybe in a specific package) would I use to
perform a Cochran C Test for Homogeneity of Variances?
Stats package have the mantelhaen.test, but I’m “almost sure” that It’s not
what I want, it’s probably the Cochran Q Test.
So, any ideas?
Thank you for the pacience.
2010 Jan 05
2
Checking for normality and homogeneity of variance
Dear all,
I'm a beginner of R and I need to carry out some three-way mixed ANOVAs.
Following examples at http://personality-project.org/r/r.anova.html, I
managed to get the ANOVA part, but I don't know how can I check data
normality and homogeneity of variance in R (since they're the required
assumptions of ANOVA analysis).
Are there any special command/packages? Could anyone give me
2005 Oct 18
4
Efficient ways of finding functions and Breslow-Day test for homogeneity of the odds ratio
Dear all,
I have been trying to find a function to calculate the Breslow-Day test for
homogeneity of the odds ratio in R. I know the test can be preformed in SAS
but i was wondering if anyone could help me to perform this in r.
In addition i have the fullrefman file to search for functions in the basic
R packages, does anyone have any suggestions of an efficient way of
searching for
2004 Apr 13
2
Non-homogeneity of variance - decreasing variance
Hello all,
I'm running very simple regression but face a problem of non-homogeneity of
variance, but with a decreasing variance with increasing mean...I do not
know how to deal with that.
this relationship doesn't seem to be strong, but it's my first time to see
something like that, and would like to know what to do if one day it becomes
stronger. I tested just for fun some
2007 Nov 15
1
homogenity inside groups
Dear all
I would like to show my audience that some variables are homogenous inside
groups but different outside. I can use by with summary for all variables
by(iris[,1:4], iris$Species, summary)
what can be quite messy in case of more than few variables and about 8
groups
or densityplot for one variable
densityplot(~Petal.Length | Species, iris)
I have two questions:
1. Is there
2010 Sep 13
2
Homogeneity of regression slopes
Hello,
We've got a dataset with several variables, one of which we're using
to split the data into 3 smaller subsets. (as the variable takes 1 of
3 possible values).
There are several more variables too, many of which we're using to fit
regression models using lm. So I have 3 models fitted (one for each
subset of course), each having slope estimates for the predictor
variables.
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
2008 Aug 27
0
[PATCH] stubdom: add v?errx? and v?warnx? functions
stubdom: add v?errx? and v?warnx? functions
Signed-off-by: Samuel Thibault <samuel.thibault@eu.citrix.com>
diff -r 14a9a1629590 extras/mini-os/include/posix/err.h
--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/extras/mini-os/include/posix/err.h Wed Aug 27 10:29:36 2008 +0100
@@ -0,0 +1,15 @@
+#ifndef _POSIX_ERR_H
+#define _POSIX_ERR_H
+
+#include <stdarg.h>
+
+void err(int eval,
2008 Apr 16
1
Brown-Forsythe F* Statistic
I've been searching around for a function for computing the
Brown-Forsythe F* statistic which is a substitute for the normal ANOVA
F statistic for when there are unequal variances, and when there is
evidence of non-normality. A couple of other people have asked this
question, the responses I found have been:
?oneway.test
However, that function appears to use the Welch W statistic which,