Displaying 20 results from an estimated 3000 matches similar to: "type III effect from glm()"
2009 Mar 10
1
help structuring mixed model using lmer()
Hi all,
This is partly a statistical question as well as a question about R, but I am stumped!
I have count data from various sites across years. (Not all of the sites in the study appear in all years). Each site has its own habitat score "habitat" that remains constant across all years.
I want to know if counts declined faster on sites with high "habitat" scores.
I can
2009 Feb 04
2
data editor in R- could it be improved?
Hi all,
I've used R for basic programming and data management for a few years now. One of the things that I think could be improved is the data editor.
Its a great feature and I use it alot by calling edit(data.frame); very useful to see if what you tried to do actually worked.
However, one of the annoying things about it is that when you scroll down the window it doesnt show you all the
2009 May 29
1
data manipulation involving aggregate
hi all,
I often have a data frame like this example
data.frame(sq=c(1,1,1,2,2,3,3,3,3),area=c(1,2,3,1,2,3,1,2,3),habitat=c("garden","garden","pond","field","garden","river","garden","field","field"))
for each "sq" I have multiple "habitat"s each with an associated "area".
I
2009 Jan 22
1
help using zeroinfl()
Hi all,
I have been trying to use zeroinfl() with the pscl package with R version 2.1.1. and with the newest versions of the contrib packages compatible with R 2.1.1.
I have read the examples, the vignette and all the posts relating to zeroinfl() but I am still confused as to how to structure the model.
Here is a small example; the error message is the same for big data sets
2009 Jun 18
1
win.metafile() and family
Hi all,
I recently discovered how great win.metafile is for getting high resolution graphics into word.
Having problems with specifying families though...
#pdf works fine
pdf("test.pdf",width=14,height=9)
par(family="Helvetica")
plot(1:10)
text(4,4,"trial")
dev.off()
windows
2
#metafile doesnt like helvetica family
2009 Apr 09
1
reading an image and adding a legend
Hi all,
I would like to
1. Read in an arcmap image into R (I can export pretty much any type of image jpeg, bitmap etc from arcmap)
2. Use R to create a nice colour legend in the plot
First of all, Is this possible?
So far I'm stuck on point 1. I have tried read.pnm() from pixmap and read.jpeg() from rgl.
the pnm example provided works fine
x <-
2006 Aug 16
1
[SPAM] - RE: REML with random slopes and random intercepts giving strange results - Bayesian Filter detected spam
Can you provide the summary(m2) results?
> -----Original Message-----
> From: Simon Pickett [mailto:S.Pickett at exeter.ac.uk]
> Sent: Wednesday, August 16, 2006 7:14 AM
> To: Doran, Harold
> Cc: r-help at stat.math.ethz.ch
> Subject: [SPAM] - RE: [R] REML with random slopes and random
> intercepts giving strange results - Bayesian Filter detected spam
>
> Hi again,
2006 Aug 15
1
REML with random slopes and random intercepts giving strange results
Hi everyone,
I have been using REML to derive intercepts and coeficients for each
individual in a growth study. So the code is
m2 <- lmer(change.wt ~ newwt+(newwt|id), data = grow)
Calling coef(model.lmer) gives a matrix with this information which is
what I want. However, as a test I looked at each individual on its own and
used a simple linear regression to obtain the same information, then
2002 Apr 15
8
Problem
Hello! If I have a matrix as 1 2
2 3
and I want to change the value 2 in 0, what can I do?
Thank you
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2011 Sep 03
2
problem in applying function in data subset (with a level) - using plyr or other alternative are also welcome
Dear R experts.
I might be missing something obvious. I have been trying to fix this problem
for some weeks. Please help.
#data
ped <- c(rep(1, 4), rep(2, 3), rep(3, 3))
y <- rnorm(10, 8, 2)
# variable set 1
M1a <- sample (c(1, 2,3), 10, replace= T)
M1b <- sample (c(1, 2,3), 10, replace= T)
M1aP1 <- sample (c(1, 2,3), 10, replace= T)
M1bP2 <- sample (c(1, 2,3), 10, replace= T)
2014 Mar 17
5
LD50
Quiero comparar varias dosis letales 50% (LD50) usando análisis probit. He
seguido un ejemplo que viene en paquete DRC, pero no obtengo el resultado
esperado. Lo que quiero es saber si las LD50s, son diferentes y si la
diferencias son estadísticamente significativas.
Gracias de antemano.
José Arturo
e-mail. jafarfan@uady.mx <grejon@uady.mx>
e-mail alterno. jafarfan@gmail.com
2012 Apr 10
1
compare two matrices
Dear Members,
I have two estimated transition matrices and I want to compare them.
In fact I want to check the hypothesis if they come from the same process.
I tried to look for some test but all I found was independence test of
contingency tables.
The following code shows that the usual chi-squared test statistic does
not follow chisq distribution.
MCRepl <- 5000
khi12 <- rep(0,MCRepl)
2009 Feb 18
1
ggplot2 Y axis labels
Hi all:
Using the example below, is there a way to add Y axis titles to each graphic instead of sharing the same title?
library(ggplot2)
RT = matrix(c(814, 500, 424, 394, 967, 574, 472, 446),4,2)
colnames(RT) = c('repetition','alternation')
rownames(RT) = c('7-yrs','11-yrs','15-yrs','21-yrs')
rt <- melt(RT)
names(rt) <- c("age",
2007 Apr 03
2
HPDinterval problem
Hi,
Can anyone tell me why I am not getting the correct intervals for
fixed effect terms for the following generalized linear mixed model
from HPDinterval:
> sessionInfo()
R version 2.4.1 (2006-12-18)
i386-pc-mingw32
locale:
LC_COLLATE=English_United States.1252;LC_CTYPE=English_United
States.1252;LC_MONETARY=English_United
States.1252;LC_NUMERIC=C;LC_TIME=English_United States.1252
2003 Mar 12
2
quasipoisson, glm.nb and AIC values
Dear R users,
I am having problems trying to fit quasipoisson and negative binomials glm.
My data set
contains abundance (counts) of a species under different management regimens.
First, I tried to fit a poisson glm:
> summary(model.p<-glm(abund~mgmtcat,poisson))
Call:
glm(formula = abund ~ mgmtcat, family = poisson)
.
.
.
(Dispersion parameter
2009 Oct 05
2
GLM quasipoisson error
Hello,
I'm having an error when trying to fit the next GLM:
>>model<-glm(response ~ CLONE_M + CLONE_F + HATCHING
+(CLONE_M*CLONE_F) + (CLONE_M*HATCHING) + (CLONE_F*HATCHING) +
(CLONE_M*CLONE_F*HATCHING), family=quasipoisson)
>> anova(model, test="Chi")
>Error in if (dispersion == 1) Inf else object$df.residual :
missing value where TRUE/FALSE needed
If I fit
2006 Aug 10
1
help with structuring random factors using lmer()
Hi,
I am an R beginner and having problems structuring my REML models. I have
a model with
y=weight
x1=time
x2=timesquared
id=individual identity
I need to structure the model such that in the random effects there is a
constant intercept for all individuals but a separate individual slope for
both x1 and x2 (a coefficient score for every individual).
2010 Sep 11
3
confidence bands for a quasipoisson glm
Dear all,
I have a quasipoisson glm for which I need confidence bands in a graphic:
gm6 <- glm(num_leaves ~ b_dist_min_new, family = quasipoisson, data = beva)
summary(gm6)
library('VIM')
b_dist_min_new <- as.numeric(prepare(beva$dist_min, scaling="classical", transformation="logarithm")).
My first steps for the solution are following:
range(b_dist_min_new)
2010 Sep 12
1
R-equivalent Stata command: poisson or quasipoisson?
Hello R-help,
According to a research article that covers the topic I'm analyzing,
in Stata, a Poisson pseudo-maximum-likelihood (PPML) estimation can be
obtained with the command
poisson depvar_ij ln(indepvar1_ij) ln(indepvar2_ij) ...
ln(indepvarN_ij), robust
I looked up Stata help for the command, to understand syntax and such:
www.stata.com/help.cgi?poisson
Which simply says
2009 Aug 13
2
Fitting a quasipoisson distribution to univariate data
Dear all,
I am analyzing counts of seabirds made from line transects at sea.
I have been fitting Poisson and negative binomial distributions to the data
using the goodfit function from the vcd library. I would also like to
evaluate how well a quasi-poisson distribution fits the data. However, none
of the potentially suitable functions I have identified (goodfit(vcd),
fitdistr(MASS),