Displaying 20 results from an estimated 20000 matches similar to: "apply: new behaviour for factors in R-2.4.0"
2006 Apr 25
1
summary.lme: argument "adjustSigma"
Dear R-list
I have a question concerning the argument "adjustSigma" in the
function "lme" of the package "nlme".
The help page says:
"the residual standard error is multiplied by sqrt(nobs/(nobs -
npar)), converting it to a REML-like estimate."
Having a look into the code I found:
stdFixed <- sqrt(diag(as.matrix(object$varFix)))
if (object$method
2005 Nov 18
1
using a factor as col argument in plot:
Dear R core team
Using the following code produces an empty plot (similar
to col = NA):
> plot(1:9, col = factor(rep(1:3,3), labels = c("red", "blue", "black")))
My question: Shouldn't one get at least a warning (or an error)
if one tries to use a factor as col argument?
Thanks for an answer.
Regards,
Christoph Buser
2006 Mar 15
2
difftime arguments
Hi
I just started using RGui.exe under widnows.
I have a text file containing date arranged in columns and rows, each column has the same format, each row with different formats. 3 of the columns are something like this 1/12/2006 3:59:45 PM
I need to calculate the different in seconds between 2 selected periods using their row’s index
My solution:
Read the file in a data frame and
2005 Jul 19
1
initial points for arms in package HI
Dear R-users
I have a problem choosing initial points for the function arms()
in the package HI
I intend to implement a Gibbs sampler and one of my conditional
distributions is nonstandard and not logconcave.
Therefore I'd like to use arms.
But there seem to be a strong influence of the initial point
y.start. To show the effect I constructed a demonstration
example. It is reproducible
2007 Jun 19
2
Preconditions for a variance analysis
Hello everbody,
i'm currently using the anova()-test for a small data.frame of 40
rows and 2 columns. It works well, but is there any preconditions for
a valid variance analysis, that i should consider?
Thank you for your answer,
Daniel
2006 Nov 15
1
how to compute p-value?
Hi all,
I just want to understand how R computes p-value in a simple linear
regression model? The reason is that in Matlab in the
function which "evaluate standard errors for multivariate normal
regression", it just provide estimates and standard errors, without giving
out p-value,
It computes t-statistics as follows:
abs(beta_hat/std_beta_hat)
how to go further to get p-value?
2006 May 17
0
variable colnames
Hy all,
I apologize i've used rownames instead of colnames in my first exemple. (that's why i changed the mail object) I was on mars when i wrote my question...
Every answer where correct ... but, because i've made a wrong question, people wern't able to understand...
So finally i'm speaking about colnames :
Let's be more precise:
I've got a query that gives me for
2005 May 15
3
adjusted p-values with TukeyHSD?
hi list,
i have to ask you again, having tried and searched for several days...
i want to do a TukeyHSD after an Anova, and want to get the adjusted
p-values after the Tukey Correction.
i found the p.adjust function, but it can only correct for "holm",
"hochberg", bonferroni", but not "Tukey".
Is it not possbile to get adjusted p-values after
2005 Jul 13
1
Name for factor's levels with contr.sum
Good morning,
I used in R contr.sum for the contrast in a lme model:
> options(contrasts=c("contr.sum","contr.poly"))
> Septo5.lme<-lme(Septo~Variete+DateSemi,Data4.Iso,random=~1|LieuDit)
> intervals(Septo5.lme)$fixed
lower est. upper
(Intercept) 17.0644033 23.106110 29.147816
Variete1 9.5819873 17.335324 25.088661
Variete2 -3.3794907 6.816101 17.011692
Variete3
2006 Sep 23
1
contrasts in aov
useRs,
A no doubt simple question, but I am baffled. Indeed, I think I
once knew the answer, but can't recover it. The default contrasts
for aov (and lm, and...) are contr.treatment and contr.poly for
unordered and ordered factors, respectively. But, how does one
invoke the latter? That is, in a data.frame, how does one indicate
that a factor is an *ordered* factor such that
2006 May 11
1
t-test with autocorrelation correction
Has anyone implemented a t-test with the effective sample size
correction proposed by Dale and Fortin, Ecoscience 9(2):162-167, 2002,
using a discussion by Cressie, 1993, page 15?
thanks,
Denis
2006 Nov 06
2
comparing 2 dataframes
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2005 Aug 02
1
plotting 3 functions on same graph
hi all,
I wish to draw on the same graphic device 3 functions.
But i don't want them to be on different graph, i want to compare them on the same
I don't need mfrow or mfcol, I need something else...
1 graph on 1 device inside this graph 3 ploted function.
I saw something unsing data.frame, but i think it's overkill, and something less complicated must exist, if not why?
why not
2006 Jan 30
2
Type II SS for fixed-effect in mixed model
Hi
In mixed-model with lme()
How can I obtain Type II SS or Type III SS for fixed effect?
Thanks
Julien
2006 Feb 01
1
Randomised Block Design
Hi, I'm studying math, and i have to make an analysys using Randomised
Block Design. I have two factors, i know how to do this in Statistica, but
how to do this in R, i read some manuals but the only thing that i have
found was 2 factor ANOVA.
Please could someone help me, or give some usefull links ??
Krzytsztof Suwada
2006 Feb 20
1
Extracting variance components from lmer
Hi All.
I need a bit of help extracting the residual error variance from the VarCorr
structure from lmer.
#Here's a 2-way random effects model
lmer.1 <- lmer(rating ~ (1|person)+(1|rater), data = dat)
#Get the structure
vc.fit <- VarCorr(lmer.1)
#results in.....
$person
1 x 1 Matrix of class "dpoMatrix"
(Intercept)
(Intercept) 0.7755392
$rater
1 x 1 Matrix
2005 Jul 07
1
How to get the minimum ?
Hi,
I have a model with differents observations Xi.
Each observation belongs to a group, either A or B.
I would like to minimize a fonction like :
sum( Xi - Z)^2 + sum (Xi - aZ -b)^2
A B
The first sum contains all observations from group A and the second all
observations from group B.
I want to find the Z-value wich minimize this function. a and b are predefined
parameters.
2005 Nov 23
1
Find main effect in 2-way ANOVA
Hi,
I use anova() to find interaction effect and then I need to find data with
main effect from those data with interaction effect. How to do that?
I used : anova(lm(data~factor1*factor2)), then select data with interaction
effect. Then I need to select those data also with main effect of factor1
or factor2, from previous selected data. How to do that? Many thanks for
your time on my
2005 May 10
2
filename
Hey,
I'm generating a .jpeg file for a web application passing parameters to
R via cgi. R gets the parameters by using commandArgs, which are passed
to a variable named j and z
j<-commandArgs()[3]
z<-commandArgs()[4]
Later I want to use the characters strings of the argument which the
variables are holding for my filename, e.g.:
jpeg(file="d:/data/images/jz.jpeg",...)