Displaying 20 results from an estimated 20000 matches similar to: "contrast package tutorial"
2009 Nov 22
1
Why F value and Pr are not show in summary() of an aov() result?
I have the following code. I'm wondering why summary() doesn't show F
value and Pr?
Rscript multi_factor.R
> a=3
> b=4
> c=5
> d=6
> e=7
>
> A=1:a
> B=1:b
> C=1:c
> D=1:d
> E=1:e
>
> X=matrix(nr=a*b*c*d*e,nc=5)
> colnames(X)=LETTERS[1:5]
>
> for(i_a in 1:a-1) {
+ for(i_b in 1:b-1) {
+ for(i_c in 1:c-1) {
+ for(i_d in 1:d-1) {
+
2009 Nov 05
4
The equivalence of t.test and the hypothesis testing of one way ANOVA
I read somewhere that t.test is equivalent to a hypothesis testing for
one way ANOVA. But I'm wondering how they are equivalent. In the
following code, the p-value by t.test() is not the same from the value
in the last command. Could somebody let me know where I am wrong?
> set.seed(0)
> N1=10
> N2=10
> x=rnorm(N1)
> y=rnorm(N2)
> t.test(x,y)
Welch Two Sample t-test
data:
2009 Sep 17
2
What does model.matrix() return?
Hi,
I don't understand what the meaning of the following lines returned by
model.matrix(). Can somebody help me understand it? What can they be
used for?
attr(,"assign")
[1] 0 1 2 2
attr(,"contrasts")
attr(,"contrasts")$A
[1] "contr.treatment"
attr(,"contrasts")$B
[1] "contr.treatment"
Regards,
Peng
> a=2
> b=3
> n=4
2010 Feb 09
1
"1 observation deleted due to missingness" from summary() on the result of aov()
I have the R code at the end. The last command gives me "1 observation
deleted due to missingness". I don't understand what this error
message. Could somebody help me understand it and how to fix the
problem?
> summary(afit)
Df Sum Sq Mean Sq F value Pr(>F)
A 2 0.328 0.16382 0.1899 0.82727
B 3 2.882 0.96057 1.1136 0.34644
C
2009 Sep 15
1
coefficients of aov results has less number of elements?
Hi,
I run the following commands. 'A' has 3 levels and 'B' has 4 levels.
Should there be totally 3+4 = 7 coefficients (A1, A2, A3, B1, B2, B3,
B4)?
> a=3
> b=4
> n=1000
> A = rep(sapply(1:a,function(x){rep(x,n)}),b)
> B = as.vector(sapply(sapply(1:b, function(x){rep(x,n)}), function(x){rep(x,a)}))
> Y = A + B + rnorm(a*b*n)
>
> fr =
2009 Sep 14
2
What are the return values of aov?
Hi,
I don't quite understand what are the return values of aov. I know
that it has 'coefficients'. But I need to know what all the other
return values are. Can somebody let me know how to figure them?
Value:
An object of class 'c("aov", "lm")' or for multiple responses of
class 'c("maov", "aov", "mlm",
2009 Sep 22
1
Singular model.matrix of nested designs
Hi,
I want to do ANOVA for nested designs like following. I don't
understand why the matrix (t(X) %*% X) is singular. Can somebody help
me understand it?
Regards,
Peng
> a=2
> b=3
> n=4
> A = as.vector(sapply(1:a,function(x){rep(x,b*n)}))
> B = as.vector(sapply(1:(a*b), function(x){rep(x,n)}))
> cbind(A,B)
A B
[1,] 1 1
[2,] 1 1
[3,] 1 1
[4,] 1 1
[5,] 1 2
[6,] 1 2
[7,]
2012 Dec 30
4
[LLVMdev] git repository of the tutorial
Hi,
I'm learning the tutorial.
http://llvm.org/docs/tutorial/
I'm wondering if there is already a git repository of the examples in
the tutorial so that I don't have to copy the code from the webpage.
Thanks!
--
Regards,
Peng
2009 Sep 15
2
syntax of formula
Hi,
I am looking for a complete description of the syntax of the formula
that shall be specified in, for example, aov. But I can't find a
complete description. Can somebody point to me if there is such a
resource?
Regards,
Peng
2005 Mar 10
1
contrast matrix for aov
How do we specify a contrast interaction matrix for an ANOVA model?
We have a two-factor, repeated measures design, with
Cue Direction (2) x Brain Hemisphere(2)
Each of these has 2 levels, 'left' and 'right', so it's a simple 2x2 design
matrix. We have 8 subjects in each cell (a balanced design) and we want to
specify the interaction contrast so that:
CueLeft>CueRght
2013 Jan 01
1
[LLVMdev] git repository of the tutorial
Hello Peng Yu,
I found the same error on my Macbook Air.
This was my first trying on MacOS X.
Troubleshooting this might take sometime.
Only thing I can say now that klang is tested successfully on Ubuntu with
- LLVM 3.2 official release on LLVM download page
- LLVM svn latest update
Clang compile produces an error message on MacOS X with the LLVM svn
latest update
I am trying to find the
2001 Oct 23
1
summary of aov fit on a contrast basis
Hello,
In a book (David W. Stockburger, "Multivariate Statistics: Concepts,
Models, and Applications", chapter 12 "Contrasts, Special and
Otherwise", available online at http://www.psychstat.smsu.edu/multibook)
I've found some examples of doing analysis of variance on a contrast
basis.
I attach my solution (in R, the book uses SPSS) to this problem.
Am I computing the
2012 Dec 30
0
[LLVMdev] git repository of the tutorial
Hello Peng Yu and List,
I have put toy.cpp into github but it has a form of LLVM project
makefile infrastructure. So you can build it together with LLVM
Project source tree.
git://github.com/Journeyer/klang.git
There exist many branches and each branch is for each chapter of Kaleidoscope.
Regards
Journeyer
2012/12/30 Peng Yu <pengyu.ut at gmail.com>:
> Hi,
>
> I'm learning
2002 May 30
0
se.contrast: matrix contrast.obj doesn't work as documented (PR#1613)
The man page for se.contrast, when describing the contrast.obj
parameter, states that "Multiple contrasts should be specified
by a matrix as returned by contrasts."
When doing an unbalanced single factor ANOVA, using a contrast.obj
as returned by contrasts results in the following error from
qr.qty when se.contrast is called:
Error in qr.qty(object$qr, contrast) : qr and y must have
2007 Feb 14
1
se.contrast confusion
Hello,
I've got what I'd expect to be a pretty simple issue: I fit an aov object
using multiple error strata, and would like some significance tests for the
contrasts I specified.
In this contrived example, I model some test score as the interaction of a
subject's gender and two emotion variables (angry, happy, neutral), measured
at entry to the experiment (entry) and later
2012 Dec 30
3
[LLVMdev] git repository of the tutorial
On Sat, Dec 29, 2012 at 7:30 PM, Journeyer J. Joh
<oosaprogrammer at gmail.com> wrote:
> Hello Peng Yu and List,
>
> I have put toy.cpp into github but it has a form of LLVM project
> makefile infrastructure. So you can build it together with LLVM
> Project source tree.
>
> git://github.com/Journeyer/klang.git
>
> There exist many branches and each branch is for
2005 Feb 20
1
Treatment-Contrast Interactions
Hello all,
(Apologies in advance if my terminology is incorrect, I'm relatively new
to R and statistics).
I have data from a factorial design with two treatments (CRF-23), and
I'm trying to compute treatment-contrast interactions through analysis
of variance. I can't figure out how to do contrasts properly, despite
reading the help for "C" and "contrasts"
2003 Oct 08
1
Contrast specified with C() - R vs S-Plus problem
Hi,
For a n-level factor, I'd like to specify the first contrast and have
the remaining n-2 constructed automatically so that the set is
orthogonal. I then test the contrasts with summary.lm(anova-object).
In S-Plus, the following works:
>y.anova <- aov( y ~ C(CO2,c(1,0,-1)) )
>summary.lm(y.anova)
In R, it fails with the following error:
>levels(CO2)
[1]
2012 Dec 30
0
[LLVMdev] git repository of the tutorial
Klang is tested with LLVM 3.1
Header file location is often changed. I guess that's why..
What version of LLVM do you use?
2012/12/30 Peng Yu <pengyu.ut at gmail.com>:
> On Sat, Dec 29, 2012 at 7:30 PM, Journeyer J. Joh
> <oosaprogrammer at gmail.com> wrote:
>> Hello Peng Yu and List,
>>
>> I have put toy.cpp into github but it has a form of LLVM project
2005 Feb 16
2
problem with se.contrast()
I am having trouble getting standard errors for contrasts using se.contrast() in
what appears to be a simple case to me. The following test example illustrates
my problem:
Lab <- factor(rep(c("1","2","3"),each=12))
Material <- factor(rep(c("A","B","C","D"),each=3,times=3))
Measurement <-