Displaying 20 results from an estimated 20000 matches similar to: "unbalanced one-way ANOVA"
2002 Mar 08
3
Unbalanced ANOVA in R?
Hi all
I'm trying to complete a textbook example originally designed for SPSS
in R, and I therefore need to find out how to compute an unbalanced
ANOVA in R.
I did a search on the mailinglist archives an found a post by Prof.
Ripley saying one should use the lme function for (among other things)
unbalanced ANOVAs, but I have not been able to use this object.
My code gives me an error.. Why
2011 Apr 03
2
Unbalanced Anova: What is the best approach?
I have a three-way unbalanced ANOVA that I need to calculate (fixed effects
plus interactions, no random effects). But word has it that aov() is good
only for balanced designs. I have seen a number of different recommendations
for working with unbalanced designs, but they seem to differ widely (car,
nlme, lme4, etc.). So I would like to know what is the best or most usual
way to go about working
2004 Jul 29
2
aov for unbalanced design (PR#7144)
Full_Name: Tanya Logvinenko
Version: 1.7.0
OS: Windows 2000
Submission from: (NULL) (132.183.156.125)
For unbalanced design, I ran into problem with ANOVA (aov function). The sum of
squares for only for the second factor and total are computed correctly, but sum
of squares for the first factor is computed incorreclty. Changing order of
factors in the formula changes the ANOVA table. For the
2012 Aug 14
2
anova in unbalanced data
Hi all,
Say I have the following data:
a<-data.frame(col1=c(rep("a",5),rep("b",7)),col2=runif(12))
a_aov<-aov(a$col2~a$col1)
summary(aov)
Note that there are 5 observations for a and 7 for b, thus is
unbalanced. What would be the correct way of doing anova for this set?
Thanks,
Sachin
[[alternative HTML version deleted]]
2011 May 21
2
unbalanced anova with subsampling (Type III SS)
Hello R-users,
I am trying to obtain Type III SS for an ANOVA with subsampling. My design
is slightly unbalanced with either 3 or 4 subsamples per replicate.
The basic aov model would be:
fit <- aov(y~x+Error(subsample))
But this gives Type I SS and not Type III.
But, using the drop() option:
drop1(fit, test="F")
I get an error message:
"Error in
2007 Sep 14
2
unbalanced effects in aov
Hi, I have been having some trouble using aov to do an anova, probably because I'm not understanding how to use this function correctly. For some reason it always tells me that "Estimated effects may be unbalanced", though I'm not sure what this means. Is the formula I am using written incorrectly? Below is the code I am using along with the data:
> my.data
response
2007 Nov 04
4
Why can repeated measures anova with within & between subjects design not be done if group sizes are unbalanced?
Dear R people:
I wish to switch from SPSS to R, but there is one particular type of
ANOVA design that cannot be done in R. Or more likely, it can be
done, but it is nowhere documented.
The problem is typical for psychologists:
You have a repeated measures design with different groups of subjects.
Now, this can be done with the aov command, but the number of
subjects in both groups must be
2010 Oct 17
1
unbalanced repeated measurements Anova with mixed effects
Dear R-list members,
I've been struggling with the proper setup for analysing my data. I've
performed a route choice experiment, in which participants had to make a
choice at each junction for the next road. During the experiment they
received traffic information, but also encountered two different
accidents. They also made trips without accidents.
What I'm interested in is to
2011 Apr 21
1
one-way ANOVA model, with one factor, an unbalanced design and unequal variances
Hi,
i'm looking for an R function to fit a one-way ANOVA with one factor
containing 10 levels. The factor levels have different numbers of
observations (varying between 20 to 40). For most of the dependent variables
i'm testing there are unequal variances among the factor levels.
I see the function oneway.test:
oneway.test(variable ~ factor, data=dataset)
which by default does not
2013 Apr 17
1
Anova unbalanced
Hello everybody,
I have got a data set with about 400 companies. Each company has a
score for its enviroment comportment between 0 and 100. These companies
belong to about 15 different countries. I have e.g. 70 companies from
UK and 5 from Luxembourg,- so the data set is pretty unbalanced and I
want to do an ANOVA. Somthing like aov(enviromentscore~country). But the
aov function is just for
2012 Jul 23
2
drop1, 2-way Unbalanced ANOVA
Hi all,
I've spent quite a lot of time searching through the help lists and reading
about how best to run perform a 2-way ANOVA with unbalanced data. I realize
this has been covered a great deal so I was trying to avoid adding yet
another entry to the long list considering the use of different SS, etc.
Unfortunately, I have come to the point where I feel I have to wade in and
see if someone
2010 Jul 13
2
how to extract information from anova results
Hi,
I have used the instruction aov in the following manner:
res <- aov(qwe ~ asd)
when I typed "res" I get:
_________
Call:
aov(formula = qwe ~ asd)
Terms:
asd Residuals
Sum of Squares 0.0708704 0.5255957
Deg. of Freedom 1 8
Residual standard error: 0.2563191
Estimated effects may be unbalanced
_________
I need to access the value of
2004 Dec 01
2
unbalanced design
Hi all,
I'm new to R and have the following problem:
I have a 2 factor design (a has 2 levels, b has 3 levels). I have an
object kidney.aov which is an aov(y ~ a*b), and when I ask for
model.tables(kidney.avo, se=T) I get the following message along with
the table of effects:
Design is unbalanced - use se.contrast() for se's
but the design is NOT unbalanced... each fator level
2005 Apr 20
6
Anova - adjusted or sequential sums of squares?
Hi
I am performing an analysis of variance with two factors, each with two
levels. I have differing numbers of observations in each of the four
combinations, but all four combinations *are* present (2 of the factor
combinations have 3 observations, 1 has 4 and 1 has 5)
I have used both anova(aov(...)) and anova(lm(...)) in R and it gave the
same result - as expected. I then plugged this into
2011 Jan 08
1
Anova with repeated measures for unbalanced design
Dear all,
I need an help because I am really not able to find over internet a good example
in R to analyze an unbalanced table with Anova with repeated measures.
For unbalanced table I mean that the questions are not answered all by the same
number of subjects.
For a balanced case I would use the command
aov1 = aov(response ~ stimulus*condition + Error(subject/(stimulus*condition)),
data=scrd)
2005 Apr 05
5
Help with three-way anova
Hi
I have data from 12 subjects. The measurement is log(expression) of a
particular gene and can be assumed to be normally distributed. The 12
subjects are divided into the following groups:
Infected, Vaccinated, Lesions - 3 measurements
Infected, Vaccintaed, No Lesions - 2 measurements
Infected, Not Vaccinated, Lesions - 4 measurements
Uninfected, Not Vaccinated, No Lesions - 3 measurements
2006 Aug 26
5
Type II and III sum of square in Anova (R, car package)
Hello everybody,
I have some questions on ANOVA in general and on ANOVA in R particularly.
I am not Statistician, therefore I would be very appreciated if you answer
it in a simple way.
1. First of all, more general question. Standard anova() function for lm()
or aov() models in R implements Type I sum of squares (sequential), which
is not well suited for unbalanced ANOVA. Therefore it is better
2011 Feb 27
1
two-way unbalanced ANOVA
Hello Everyone,
*Question: *How do you calculate the sum of squares for a two-way
_unbalanced_ ANOVA?
*What I have done:*
I have found many useful tutorials online for running a balanced two-way
ANOVA but I haven't had much luck for running a unbalanced two-way
ANOVA. From what I have read, the trouble with running an unbalanced
two-way ANOVA, is that things get tricky when calculating
2010 Jul 28
1
specifying an unbalanced mixed-effects model for anova
hi all - i'm having trouble using lme to specify a mixed effects
model.
i'm pretty sure this is quite easy for the experienced anova-er, which
i unfortunately am not.
i have a data frame with the following columns:
col 1 : "Score1" (this is a continuous numeric measure between 0 and
1)
col 2 : "Score2" (another continuous numeric measure, this time
bounded between 0
2012 Nov 27
2
Anova
Hi everyone,
I am new to this forum and also new to statistics and I would appreciated it
if someone would take some time to answer my question.
I am analyzing companies in regard to their leverage. I categorized the
companies into 3 groups: small, mid and large. For the group small, I have
55 debt multiples, for mid 42 and for large 72. (Unfortunately I can not
provide my data because it is