Displaying 20 results from an estimated 600 matches similar to: "Multiple tests on 2 way-ANOVA"
2003 May 19
1
multcomp and glm
I have run the following logistic regression model:
options(contrasts=c("contr.treatment", "contr.poly"))
m <- glm(wolf.cross ~ null.cross + feature, family = "binomial")
where:
wolf.cross = likelihood of wolves crossing a linear feature
null.cross = proportion of random paths that crossed a linear feature
feature = CATEGORY of linear feature with 5 levels:
2006 Jul 25
1
Multiple tests on repeated measurements
Dear R-helpers:
My question is how do I efficient and valid correct for multiple tests in a repeated measurement design:
Suppose we measure at two distinct visits with repeated subjects a treatment difference on the same variable.
The treatment differences are assessed with a mixed model and adjusted by two methods for multiple tests:
# 1. Method: Adjustment with library(multcomp)
2006 Feb 07
1
post-hoc comparisons following glmm
Dear R community,
I performed a generalized linear mixed model using glmmPQL (MASS
library) to analyse my data i.e : y is the response with a poisson
distribution, t and Trait are the independent variables which are
continuous and categorical (3 categories C, M and F) respectively, ind
is the random variable.
mydata<-glmmPQL(y~t+Trait,random=~1|ind,family=poisson,data=tab)
Do you think it
2012 Oct 13
4
Problems with coxph and survfit in a stratified model with interactions
I?m trying to set up proportional hazard model that is stratified with
respect to covariate 1 and has an interaction between covariate 1 and
another variable, covariate 2. Both variables are categorical. In the
following, I try to illustrate the two problems that I?ve encountered, using
the lung dataset.
The first problem is the warning:
To me, it seems that there are too many dummies
2012 Oct 14
1
Problems with coxph and survfit in a stratified model, with interactions
First, here is your message as it appears on R-help.
On 10/14/2012 05:00 AM, r-help-request@r-project.org wrote:
> I?m trying to set up proportional hazard model that is stratified with
> respect to covariate 1 and has an interaction between covariate 1 and
> another variable, covariate 2. Both variables are categorical. In the
> following, I try to illustrate the two problems that
2003 Apr 28
2
stepAIC/lme problem (1.7.0 only)
I can use stepAIC on an lme object in 1.6.2, but
I get the following error if I try to do the same
in 1.7.0:
Error in lme(fixed = resp ~ cov1 + cov2, data = a, random = structure(list( :
unused argument(s) (formula ...)
Does anybody know why?
Here's an example:
library(nlme)
library(MASS)
a <- data.frame( resp=rnorm(250), cov1=rnorm(250),
cov2=rnorm(250),
2012 Jul 06
2
Anova Type II and Contrasts
the study design of the data I have to analyse is simple. There is 1 control group (CTRL) and 2 different treatment groups (TREAT_1 and TREAT_2).
The data also includes 2 covariates COV1 and COV2. I have been asked to check if there is a linear or quadratic treatment effect in the data.
I created a dummy data set to explain my situation:
df1 <- data.frame(
Observation =
2008 Aug 18
1
lmer syntax, matrix of (grouped) covariates?
I have a fairly large model:
> length(Y)
[1] 3051
> dim(covariates)
[1] 3051 211
All of these 211 covariates need to be nested hierarchically within a
grouping "class", of which there are 8. I have an accessory vector, "
cov2class" that specifies the mapping between covariates and the 8 classes.
Now, I understand I can break all this information up into individual
2010 Jan 30
2
Questions on Mahalanobis Distance
Hello,
I am a new R user and trying to learn how to implement the mahalanobis
function to measure the distance between to 2 population centroids. I
have used STATISTICA to calculate these differences, but was hoping to learn
to do the analysis in R. I have implemented the code as below, but my
results are very different from that of STATISTICA, and I believe I may not
have interpreted the help
2011 Dec 22
1
overlaid filled contour plots
I'm trying to make a set of contour plots of bivariate kernel density
estimates, showing three such plots overlaid,
similar to this plot
http://euclid.psych.yorku.ca/SCS/Private/Test/ridge-boot2.pdf
except that I would like to have the contours *filled* (using
transparent colors). To make this reproducible, I've
saved the results of KernSmooth::bkde2D() in the following file:
2013 Oct 18
1
crr question in library(cmprsk)
Hi all
I do not understand why I am getting the following error message. Can
anybody help me with this? Thanks in advance.
install.packages("cmprsk")
library(cmprsk)
result1 <-crr(ftime, fstatus, cov1, failcode=1, cencode=0 )
one.pout1 = predict(result1,cov1,X=cbind(1,one.z1,one.z2))
predict.crr(result1,cov1,X=cbind(1,one.z1,one.z2))
Error: could not find function
2009 Aug 02
1
Competing Risks Regression with qualitative predictor with more than 2 categories
Hello,
I have a question regarding competing risk regression using cmprsk package (function crr()). I am using R2.9.1. How can I do to assess the effect of qualitative predictor (gg) with more than two categories (a,b,c) categorie c is the reference category. See above results, gg is considered like a ordered predictor !
Thank you for your help
Jan
> # simulated data to test
> set.seed(10)
2010 Jan 29
2
Vectors with equal sd but different slope
Hi,
what I would need are 2 vector pairs (x,y) and (x1,y1). x and x1 must have
the same sd. y and y1 should also exhibit the same sd's but different ones
as x and x1. Plotting x,y and x1,y1 should produce a plot with 2 vectors
having a different slope. Plotting both vector pairs in one plot with fixed
axes should reveal the different slope.
many thanks
syrvn
--
View this message in
2005 Mar 09
1
multiple comparisons for lme using multcomp
Dear R-help list,
I would like to perform multiple comparisons for lme. Can you report to me
if my way to is correct or not? Please, note that I am not nor a
statistician nor a mathematician, so, some understandings are sometimes
quite hard for me. According to the previous helps on the topic in R-help
list May 2003 (please, see Torsten Hothorn advices) and books such as
Venables &
2002 Dec 04
1
Mixture of Multivariate Gaussian Sample Data
Hey, I am confused about how to generate the sample data from a mixture of
Multivariate Gaussian ditribution.
For example, there are 2 component Gaussian with prior
probability of 0.4 and 0.6,
the means and variances are
u1=[1 1]', Cov1=[1 0;0 1]
and
u2=[-1 -1]', Cov2=[1 0;0 1]
repectively.
So how can I generate a sample of 500 data from the above mixture
distribution?
Thanks.
Fred
2003 May 05
1
multcomp and lme
I suppose that multcomp in R and multicomp in S-Plus are related and it
appears that it is possible to use multicomp with lme in S-Plus given the
following correspondence on s-news
sally.rodriguez at philips.com 12:57 p.m. 24/04/03 -0400 7 [S] LME summary
and multicomp.default()
Is it possible to use multicomp with lme in R and if so what is the syntax
from a simple readily available
2007 Nov 22
3
anova planned comparisons/contrasts
Hi,
I'm trying to figure out how anova works in R by translating the
examples in Sokal And Rohlf's (1995 3rd edition) Biometry. I've hit a
snag with planned comparisons, their box 9.4 and section 9.6. It's a
basic anova design:
treatment <- factor(rep(c("control", "glucose", "fructose",
"gluc+fruct",
2009 Mar 25
2
"with" and "by" and NA:
Hi,
I have a data.frame with many variables for which I am performing the
mean by subgroup, for a pair of variables at a time, where one of them
for each pair defines the subgroup. The subgroups in the x$cm1 are 0, 1
and 2.
x
ph1 cm1
0.2345 2
1.2222 1
2.0033 0
0.0000 2
1.0033 1
0.2345 0
1.2222 2
2.0033 0
0.0000 1
1.0033 2
> meanbygroup <- as.vector(with(x, by(x$ph1, x$cm1, mean)))
2020 May 03
2
[EXTERNAL] How to get branch coverage by using 'source-based code coverage'
Hi, Alan
Really very excited to receive your email and sorry to be slow replying, it
has been exceptionally busy over the last few days ;(
Your explanation made the problem clear to me. So gcov branch coverage
should be called condition coverage and clang region coverage
is branch coverage in fact(also known as *decision/C1*), right?
And llvm/clang will support all the following coverage
2010 Dec 08
4
evaluating NAs in a dataframe
Hi all,
How can one evaluate NAs in a numeric dataframe column? For example, I have
a dataframe (demo) with a column of numbers and several NAs. If I write
demo.df >= 10, numerals will return TRUE or FALSE, but if the value is
"NA", "NA" is returned. But if I write demo.df == "NA", it returns as "NA"
also. I know that I can remove NAs, but would like