Displaying 20 results from an estimated 3000 matches similar to: "Looking for non-central F quantile"
2003 Apr 13
2
Peculiarity in non-central qchisq for ncp > 294.92 ...
Hello all,
Here's my query:
Running R 1.6.2 on FreeBSD 5.0, and on WinXP, and I find that the
following hangs the process:
dchisq(alpha=0.01, df=1, ncp=295)
but it does work for ncp < 294.92.
Is this general?
Best wishes to all,
Andrew
Andrew Robinson Ph: 208 885 7115
Department of Forest Resources Fa: 208 885 6226
University of Idaho E : andrewr at uidaho.edu
PO
2005 Apr 19
2
Odd diagnostic plots in mixed-effects models
Dear R community,
In the excellent nlme package the default diagnostic plot graphs the innermost residuals against innermost fitted values. I recently fit a mixed-effects model in which there was a very clear positive linear trend in this plot.
I inferred that this trend occurred because my fixed effect was a two-level factor, and my random effect was a 12-level factor. The negative residuals
2004 Nov 10
1
List seems to drop empty levels of factors when containin g them
I don't get the same result, do you have a package loaded that would change
the default behavior (such as Hmisc)?
> list(grp.1)
[[1]]
[1] 1 2
Levels: 1 2
> list(grp.1[mask])
[[1]]
[1] 1
Levels: 1 2
> library(Hmisc)
<<snip>>
> list(grp.1[mask])
[[1]]
[1] 1
Levels: 1
--Matt
> version
_
platform i386-pc-mingw32
arch i386
os
2002 Jul 18
3
Oddity with names
Hi all,
I'm using R 1.5.1 on Windows 2000. The following snippet of code doesn't
seem to do anything - no error is reported, and there is no name change.
names(myFrame[,c(1:3)]) <- c("name1", "name2", "name3")
This code however works nicely:
names(myFrame)[c(1:3)] <- c("name1", "name2", "name3")
Can anyone suggest why
2002 Jul 07
2
R on Sharp Zaurus 5500?
Hello,
has anyone tried to get R running on a Sharp Zaurus 5500?
Andrew
Andrew Robinson Phone: 208-885-7115
Department of Forest Resources Fax: 208-885-6226
University of Idaho E: andrewr at uidaho.edu
Po Box 441133 WWW: http://www.uidaho.edu/~andrewr
Moscow, ID 83843 and: http://www.biometrics.uidaho.edu/
No statement above
2005 Jun 15
2
Plotting second axes outside xyplot
Hi all,
I'm trying to find a way to get xyplot to produce a second set of axes outside the right hand side of the graph. This is my progress so far:
EE <- equal.count(ethanol$E, number=9, overlap=1/4)
xyplot(NOx ~ C | EE, data = ethanol,
prepanel = function(x, y) prepanel.loess(x, y, span = 1),
xlab = "Compression Ratio", ylab = "NOx (micrograms/J)",
2003 Sep 01
1
par(new=T) works differently in pdf vs postscript if applied before a plot statement. (PR#4037)
If I place par(new=T) before I create a plot in a script that is sent to a pdf
device, the pdf is unopenable and reports itself as having no pages. The
postscript device seems to ignore the par instruction.
I guess one of these is a bug, but I don't know which one!
--please do not edit the information below--
Version:
platform = i386-pc-linux-gnu
arch = i386
os = linux-gnu
system =
2005 Jan 02
2
How to quieten axis() for Sweave: avoid echoing NULL?
Dear R-community,
I'm using Sweave to produce reports. The reports require the "axis"
command. When I run axis the program returns NULL as well as creating
the axis.
> plot(1:4, rnorm(4), axes=FALSE)
> axis(1, 1:4, LETTERS[1:4])
NULL
>
So, my Sweave tex files have
\begin{Schunk}
\begin{Soutput}
NULL
\end{Soutput}
\end{Schunk}
in front of each graphic that requires
2004 Mar 10
1
Non-linear regression problem: R vs JMP (long)
Dear R friends,
I know that this topic has been mulled over before, and that there is a
substantial difference between the convergence criteria for JMP and those for
R. I apologize that this is somwehat raking cold coals.
Summary:
A model/data combination achieves convergence in JMP, and survives a
reasonably rigorous examination (sensible parameter estimates, well-behaved
surface,
2004 Mar 23
2
Coefficients and standard errors in lme
Hello,
I have been searching for ways to obtain these for combinations of fixed
factors and levels other than the 'baseline' group (contrasts coded all
0's) from a mixed-effects model in lme. I've modelled the continuous
variable y as a function of a continuous covariate x, and fixed factors
A, B, and C. The fixed factors have two levels each and I'd like to know
whether
2004 Sep 21
2
Bootstrap ICC estimate with nested data
I would appreciate some thoughts on using the bootstrap functions in the
library "bootstrap" to estimate confidence intervals of ICC values
calculated in lme.
In lme, the ICC is calculated as tau/(tau+sigma-squared). So, for instance
the ICC in the following example is 0.116:
> tmod<-lme(CINISMO~1,random=~1|IDGRUP,data=TDAT)
> VarCorr(tmod)
IDGRUP = pdLogChol(1)
2004 Mar 10
3
converting lists got by tapply to dataframes
I have two lists:
xa <- list( X=c(1,2,3), Y=c(4,5,6), Z=c(7,8,9) )
xb <- with( barley, tapply( X=seq(1:nrow(barley)), INDEX=site
, FUN=function(z)yield[z]))
I can convert xa to a dataframe easily with:
as.data.frame(xa)
But if i try the same with xb I get:
as.data.frame(xb)
Error in as.data.frame.default(xb) :
can't coerce array into a data.frame
What
2004 Apr 06
0
Curious about nomenclature: random deviates
< Does anyone know why they're called random deviates, as opposed to random
numbers?>
Others will probably give you some technical reason about random numbers can
be considered as random deviates from a mean (I think at least the 1875
Galton paper at http://www.mugu.com/galton/ uses similar terminology (I'm
not claiming this is the earliest use - just the easiest to access at the
2004 Mar 26
8
stop() vs. error() ?
Why does stop("we are done") print
"Error in eval.with.vis(expr, envir, enclos) :" ?
It would seem to me that a plain stop() is not an error, and that it
would make more sense to have an error() function that is different from
a stop(). Is there a rationale here that I am missing?
sincerely, /iaw
2003 Oct 24
1
Dataframes of marginal summaries
Hi dear R-community,
I wonder if anyone has written code that will post-process the results of a
tapply to create a dataframe that includes the outcome, the factor by which
the function has been applied, and, if the factor is also an interaction,
then also the levels of contributing factors?
>From this
outcome <- tapply(data, A.B, function)
I'd like to arrange something like this:
2003 Dec 08
0
TukeyHSD changes if I create interaction term
Dear R community,
I'm trying to understand this behavior of TukeyHSD. My goal is to obtain
defensible, labelled multiple comparisons of an interaction term.
Firstly, if I plot the TukeyHSD from the model that calculates its own
interactions, then the y-axis labels appear to be reflected on their median
when compared to the text output of the TukeyHSD statement. The labels are
integers.
2004 May 24
1
Stopping the process after a certain time
Greetings R-community,
I'm running simulations within R that I wrote in C. The simulations
require fitting that occasionally fails to finish. I was wondering if
there is any kind of tool for process control in R, such that after e.g.
15 minutes I could kill the process, record the state for post-hoc
analysis, and move to the next simulation?
I'm running FreeBSD and could almost surely
2004 Nov 10
1
List seems to drop empty levels of factors when containing them
Greetings R community,
I am curious about the following behaviour: if I define a factor, and
then store a subset of it in a list, the stored version seems to drop
levels that were not included in the subset. E.g. ..
> mask <- c(T, F)
> grp.1 <- factor(c(1,2))
> list(grp.1)
[[1]]
[1] 1 2
Levels: 1 2
> list(grp.1[mask])
[[1]]
[1] 1
Levels: 1
It is as though the list were
2004 Apr 14
1
Aggregate drops empty subsets
Greetings, R community.
I am trying to create a multi-dimensional contingency table suitable
for analysis by glm() using the poisson family. I have three factors,
each with four levels, with some observed zeros. I'm trying to use
aggregate to construct my contingency table, but it drops empty
subsets, so the zeros get lost. I also tried tapply() but it doesn't
carry over the main
2004 Dec 13
2
Farmating printed Numbers and Text
Hello,
is there any function to print (using "cat" or "print" etc.) a table of
values row per row in a exact order, even if the value has 3 digit and in
the next row eg. 5 digits? This means I want to print a number with 3 digits
with 2 spaces in front and a number with 4 digits only with one space in
front.
regards Andreas