Displaying 20 results from an estimated 10000 matches similar to: "Problems with aov function"
2000 Mar 04
1
Nested design with aov
Hello,
I want to do this model:
Y_ml=Mu+M+L(M)+Error
M is a fixed factor with two levels, 1 and 2
L is a random factor and nested in M, with 9 levels (9 places inside
each level of M)
amarc is the dependent variable (animal abundance)
datos is the matrix
I used the next orders in R, but there is a problem with the Df
calculation:
> m
[1] 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1
1999 Dec 10
1
orthogonal and nested model
I'm working with a orthogonal and nested model (mixed).
I have four factors, A,B,C,D;
A and B are fixed and orthogonal
C is nested in AB interaction
and finally, D is nested in C.
I would like to model the following
Y_ijklm=Mu+A_i+B_j+AB_ij+C_k(ij)+D_l(k(ij))+Error_m(...)
I used the next command
>summary(aov(abund~A*B + C % in % A:B + D % in % C % in % A:B ,datos))
Is it the correct
2004 Oct 25
2
aov documentation page: question
Dear all
I was looking at the aov documentation page and came across the
following which seems like a contradiction to me:
" This provides a wrapper to |lm| for fitting linear models to balanced
or unbalanced experimental designs." (I presume 'This' refers to aov)
and
"|aov| is designed for balanced designs, and the results can be hard to
interpret without
2000 Jul 05
1
Tukey.aov with split-plot designs
I am using R 1.1 with Redhat 6.2 and RW 1.001 with Win98 (the upkey doesn't
work on my IBM either as has been previously reported by others).
The function aov doesn't return either the residuals or the residual
degrees of freedom for split-plot designs.
If you use the following code from Baron and Li's "Notes on the use of R
for psycology experiments and questionnaires"
2005 Nov 08
1
Type II and III sums of squares with Error in AOV
I've recently run into the problem of using aov with nested factors,
and wanting to get the type II and III sums of squares. Normally Anova
from the car package would do fine, but it doesn't like having an Error
included, so
my.aov <-aov(Response ~ Treatment + Error(Treatment:Replicate))
Anova(my.aov, type="II")
yields
Error in Anova(nested.anova) : no applicable method
2008 Dec 17
1
repeated measures aov with weights
Dear R-help,
I'm facing a problem with defining a repeated measures anova with
weighted data.
Here's the code to reproduce the problem:
# generate some data
seed=11
rtrep <- data.frame(rt=rnorm(100),ti=rep(1:5,20),subj=gl
(20,5,100),we=runif(100))
# model with within factor for subjects/repeated measurements, no
problem
aov(rt~ti + Error(subj/ti),data=rtrep)
#model with weights
2010 May 09
3
Question about factor that is numeric, in aov()
I notice something curious about how aov() treats a numeric factor:
"score" is a dependent variable and "group" is a factor in a one-way ANOVA.
But "group" contains numeric codes and is not a factor (checked with
is.factor). An ANOVA done using:
> aov(score~factor(group), data=mydata)
gives the right answers. But
> aov(score~group, data=mydata)
also
2008 Dec 16
2
model.tables error from aov
Hi, I'm a new R user, coming from SPSS, and without a particularly strong
stats background.
I've got a data set that I'd like to do a mixed-design ANOVA with. No
missing values. Here's the summary:
summary(learnDat.ae)
Type Subject idio struct TrainErrs cond
0:20 11 : 3 idio :28 ae :58 Min. : 0.00 idioae :28
2:19 12 : 3
2003 Mar 22
1
extracting the names of the dataframe and variables in aov or lm
Dear R Users,
I want to write a function that applies to the dataframe and variables
that were used in a previous call to lm or aov. In order to do this, I
need to write a function that applies to the output of lm or aov, and
yields the names of the dataframe and variables that were used in the lm
or aov analysis.
For example, suppose that I give the command:
aov.out <- aov( Rt ~
2008 Nov 26
1
S4 slot containing either aov or NULL
Dear listmembers,
I would like to define a class with a slot that takes either an object
of class aov or NULL. I have been reading "S4 Classes in 15 pages more
or less" and "Lecture: S4 classes and methods"
#First I tried with list and NULL
setClass(listOrNULL")
setIs("list", "listOrNULL")
setIs("NULL", "listOrNULL")
#doesn't
2008 Oct 29
2
how to get the value of aov summary into another variable
Hi,
I have a question of aov. e.g.
aov.ex = aov(x~y)
summary(aov.ex)
The aov summary will print to the screen. How can I extract the aov
result, in particular the values of Pr(>F) and F value into a vector
so that I can use them for other use?
Thanks.
--
Waverley @ Palo Alto
2004 Aug 26
1
library(car) Anova() and Error-term in aov()
Dear all,
Type III SS time again. This case trying to reproduce some SPSS (type III)
data in R for a repeated measures anova with a betwSS factor included. As I
understand this list etc, if I want type III then I can do
library(car)
Anova(lm.obj, type="III")
But for the repeated measures anova, I need to include an Error-term in the
aov() call (Psychology-guide from Jonathan Baron)
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
2010 Jan 09
2
aov function syntax
Hello,
I have a simple question about using the aov function syntax (ie. * + or :)
for the interaction of 2 factors. I have read the help files, and researched
other sites, and have included my source files. My goal is to measure the
signifigance of the interaction between population and condition (aka.
population:condition). I can't seem to figure it out.
1. In the first example the
2010 Apr 21
1
How to obtain the coefficients from a summary of aov ?
Dear Madame, Dear Sir,
I am able to obtain the coefficients from a 'summary' of 'lm', but NOT from a 'summary' of 'aov'.
The following example shows my steps.
## Initialize
rm(list = ls()) # remove (almost) everything in the working environment
utils::data(npk, package="MASS") # get data
model <- yield ~ block + N*P*K
## Using lm
npk.lm <-
2010 Nov 16
1
AOV/LME
Hi everyone,
I'm having a little trouble with working out what formula is better to use
for a repeated measures two way anova. I have two factors, L (five levels)
and T (two levels). L and T are both crossed factors (all participants do
all combinations). So, I do:
summary(aov(dat~L*T+Error(participant/(L*T)),data=dat4))
But get different results with:
2007 Jun 28
2
aov and lme differ with interaction in oats example of MASS?
Dear R-Community!
The example "oats" in MASS (2nd edition, 10.3, p.309) is calculated for aov and lme without interaction term and the results are the same.
But I have problems to reproduce the example aov with interaction in MASS (10.2, p.301) with lme. Here the script:
library(MASS)
library(nlme)
options(contrasts = c("contr.treatment", "contr.poly"))
# aov: Y ~
2006 Aug 03
3
between-within anova: aov and lme
I have 2 questions on ANOVA with 1 between subjects factor and 2 within factors.
1. I am confused on how to do the analysis with aov because I have seen two examples
on the web with different solutions.
a) Jon Baron (http://www.psych.upenn.edu/~baron/rpsych/rpsych.html) does
6.8.5 Example 5: Stevens pp. 468 - 474 (one between, two within)
between: gp
within: drug, dose
aov(effect ~ gp * drug *
2002 Jul 05
1
balance in AoV (was aov() and NaN)
<ripley at stats.ox.ac.uk> wrote:
> Hint 2: in the absence of balance, ...., and lme can do that
Would it be possible to make aov like wrappers to the various special lm variants
allowing for a uniform syntax for anova?
aov(resp~f1*f2+Error(S/(f1*f2))) ## uses lm
aov.lme(resp~f1*f2+Error(S/(f1*f2))) ## uses lme
aov.rlm(resp~f1*f2+Error(S/(f1*f2))) ## uses rlm
...
I'd do it, but I
2013 Mar 06
1
aov() and anova() making faulty F-tests
Dear useRs,
I've just encountered a serious problem involving the F-test being carried
out in aov() and anova(). In the provided example, aov() is not making the
correct F-test for an hypothesis involving the expected mean square (EMS) of
a factor divided by the EMS of another factor (i.e., instead of the error
EMS).
Here is the example:
Expected Mean Square