Displaying 20 results from an estimated 2000 matches similar to: "Post hoc Multiple comparison"
2003 May 14
1
Multiple comparison and lme (again, sorry)
Dear list,
As a reply to my recent mail:
> simint and TukeyHSD work for aov objects.
> Can someone point me to similar functions for lme objects?
Douglas Bates wrote
There aren't multiple comparison methods for lme objects because it is
not clear how to do multiple comparisons for these. I don't think the
theory of multiple comparisons extends easily to lme models. One
could
2003 Apr 03
2
Matrix eigenvectors in R and MatLab
Dear R-listers
Is there anyone who knows why I get different eigenvectors when I run
MatLab and R? I run both programs in Windows Me. Can I make R to produce
the same vectors as MatLab?
#R Matrix
PA9900<-c(11/24 ,10/53 ,0/1 ,0/1 ,29/43 ,1/24 ,27/53 ,0/1 ,0/1 ,13/43
,14/24 ,178/53 ,146/244 ,17/23 ,15/43 ,2/24 ,4/53 ,0/1 ,2/23 ,2/43 ,4/24
,58/53 ,26/244 ,0/1 ,5/43)
#R-syntax
2003 May 19
1
Syntax for random effect in glmmPQL
Dear R-listers
I wonder if someone can help me with the syntax for the random effect in
glmmPQL()? I have a data set with a response variable "y" (counts), two
dependent variables: "treat" (4 levels) and "site" (2 levels). The
latter, I want to use as a random variable. How do I specify this in the
function?
Is it like this:
2007 Oct 30
2
calculate spatial distance
Hi,
I have a set of locations defined by longitude and latitude (in degrees),
and want to calculate the spatial (or geographic) distance among all
locations.
I did not find such a function in the spatial-related packages. (I *cannot*
use 'dist', as I have geographic, not cartesian coordinates).
thanks!
Robert
Robert Ptacnik
Norwegian Institute for Water Research (NIVA)
Gaustadall?en 21
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 &
2008 Jul 04
1
kriging problem(?)
Hei,
I have two spatial datasets Sa and Sb, both with lat-lon coordinates and
from same geographic area, but from different localities within the area
(independent samples). Sa is biotoc data, Sb is some environmental
parameter (fertility). I 'know' that Sb affects Sa, but wonder on which
scale. I tried different interpolations by creating different grids of Sb
(e.g. 20x20 and 100x100
2009 Dec 04
2
csimtest function in multcomp package
Hello all,
Quick question: I want to do posthoc contrasts for a linear mixed
effects model. However, when trying to use the csimtest function in
multcomp package I receive an error message saying it cannot find the
function, even after installing and loading package multcomp.
Any pointers would be greatly appreciated
Daniel
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:
2007 Nov 28
2
fit linear regression with multiple predictor and constrained intercept
Hi group,
I have this type of data
x(predictor), y(response), factor (grouping x into many groups, with 6-20
obs/group)
I want to fit a linear regression with one common intercept. 'factor'
should only modify the slopes, not the intercept. The intercept is expected
to be >0.
If I use
y~ x + factor, I get a different intercept for each factor level, but one
slope only
if I use
y~ x *
2007 Feb 07
1
heteroscedasticity problem
Dear Listers,
I have a regression problem (x->y) with biological data, where x influences
y in two ways, (1) y increases with x and (2) the variation around the mean
(residuals) decreases with increasing x, i.e. y becomes more 'predictable'
as x increases.
The relationship is saturating, y~a + bx + cx^2, gives a very good fit.
I know basically how to test for heteroscedasticity. My
2007 Nov 29
1
relative importance of predictors
Hei Group,
I want to compare the relative importance of predictors in a multiple
linear regression y~a+bx1+cx2...
However, bptest indicates heteroskedasticity of my model. I therefore
perform a robust regression (rlm), in combination with bootstrapping (as
outlined in J. Fox, Bootstrapping Regression Models).
Now I want to compare the relative importance of my predictors. Can I rely
on the
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
2004 Feb 20
1
nlme and multiple comparisons
This is only partly a question about R, as I am not quite sure about the
underlying statistical theory either.
I have fitted a non-linear mixed-effects model with nlme. In the fixed
part of the model I have a factor with three levels as explanatory
variable. I would like to use Tukey HSD or a similar test to test for
differences between these three levels.
I have two grouping factors:
2005 Oct 14
1
smbcacls add acl fails 3.0.20
Hi all!
I have a problem setting ACLs on a remote file on a Windows XP Pro
SP2 box.
I issue the following command:
smbcacls -a 'ACL:BBI-DEV\beakid:ALLOWED/0/0x00100116' -U 'BBI-DEV
\Admin' //BBI-DEV/Data /Niva.txt
And I get this response from debug level 3.
Password:
Connecting to host=BBI-DEV
Connecting to 192.168.1.124 at port 445
Doing spnego session setup (blob
2003 Oct 08
2
binomial glm warnings revisited
Dear all,
Last autumn there was some discussion on the list of the warning
Warning message:
fitted probabilities numerically 0 or 1 occurred in: (if
(is.empty.model(mt)) glm.fit.null else glm.fit)(x = X, y = Y,
when fitting binomial GLMs with many 0 and few 1.
Parts of replies:
"You should be able to tell which coefficients are infinite -- the
coefficients and their standard errors will
2005 Oct 17
1
smbcacls add fails 3.0.20a
Hi all!
I have a problem setting ACLs on a remote file on a Windows XP Pro
SP2 box.
I issue the following command:
smbcacls -a 'ACL:BBI-DEV\beakid:ALLOWED/0/0x00100116' -U 'BBI-DEV
\Admin' //BBI-DEV/Data /Niva.txt
And I get this response from debug level 3.
Password:
Connecting to host=BBI-DEV
Connecting to 192.168.1.124 at port 445
Doing spnego session setup (blob
2005 May 23
0
using lme in csimtest
Hi group,
I'm trying to do a Tukey test to compare the means of a factor
("treatment") with three levels in an lme model that also contains the
factors "site" and "time":
model = response ~ treatment * (site + time)
When I enter this model in csimtest, it takes all but the main factor
"treatment" as covariables, not as factors (see below).
Is it
2002 Jul 01
1
How to do multiple comparisons with multiple error strata
Hello,
the title says it all. I have an ANOVA model with
"Error" term and the functions TukeyHSD or those
from the "multcomp" package seem not to work with
such a model. Assuming that the object returned from
aov() function with multiple strata is a list of aov objects,
I tried something like TukeyHSD(aov.1$Within), but this
does not work either.
Does somebody have a
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 May 21
2
more simplified output from glht object
Hi,
I use glht to make multcomp, using Tukey, from a glm model.
It is possible to get a more simplified output of result? Somethink like
ordering by letters.
Thanks
Ronaldo
--
Human kind cannot bear very much reality.
-- T. S. Eliot, "Four Quartets: Burnt Norton"
--
> Prof. Ronaldo Reis J?nior
| .''`. UNIMONTES/Depto. Biologia Geral/Lab. de Ecologia
| : :' :