Displaying 20 results from an estimated 11000 matches similar to: "pt fails with ncp"
2008 Jun 14
1
qt with ncp>37.62
help(qt) states that:
"ncp non-centrality parameter delta; currently except for rt(), only for
abs(ncp) <= 37.62"
so I would expect that calling qt with non-centrality parameter exceeding
37.62 should fail, instead e.g. calling
> mapply(function(x) qt(p = 0.9, df = 55, ncp = x),35:45)
gives:
[1] 40.21448 41.35293 42.49164 43.68862 44.82945 45.97048 47.11170 48.25310
[9]
2005 Apr 26
1
Finding 'ncp' for t
Hi Folks,
I'm looking for a neat procedure for the following:
Given t0 such that
pt(t0,df,ncp=0) = alpha (given)
find ncp0 such that for given beta
pt(t0,df,ncp=ncp0) = (1 - beta)
(In other words, what's the ncp such that you get power (1-beta)
to detect it, using a 1-sided test with size alpha when ncp = 0?)
In the past I've done the groping by hand, but this time it
needs
2003 Jul 22
6
variable names
Dear helpers
I want to use rpart several times in a loop to build a classification tree. My problem is that rpart needs a formula as argument and for that the variables need to have names and this doesn't happen in my case. Every iteration in the loop has a different dataset with several variables (ex. 38 or more) and so I can't type the names by hand every time. Is there any function
2001 Feb 26
3
%*% in examples (PR#855)
Hi,
when we add
\examples{
a <- 1:4
a %*% a
}
into a Rd-file are run R CMD check, the resulting R code is
a <- 1:4
a
So, %*% ... is lost on the way if I'm not totally confused.
Torsten
--please do not edit the information below--
Version:
platform = i686-pc-linux-gnu
arch = i686
os = linux-gnu
system = i686, linux-gnu
status = Patched
major = 1
minor = 2.0
year =
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
2001 Dec 10
1
Error on start
r-devel from this morning says
hothorn@www:~ > R
R : Copyright 2001, The R Development Core Team
Version 1.4.0 Under development (unstable) (2001-12-09)
R is free software and comes with ABSOLUTELY NO WARRANTY.
You are welcome to redistribute it under certain conditions.
Type icense()' or icence()' for distribution details.
R is a collaborative project with many contributors.
Type
2003 Mar 12
1
cex.axis in boxplot (PR#2628)
Hi,
the graphical parameter "cex.axis" does not have any affect for "boxplot":
data(iris)
boxplot(iris[,1:4], ylab="y", cex.lab=2, cex.axis=2)
The patch is simply adding "cex.axis" to the search for axis relevant
parameters in "bxp":
ax.pars <- pars[names(pars) %in% c("xaxt", "yaxt", "las",
2001 Feb 01
1
postscript and lty
To the plot experts:
when creating a plot containing different lines, each with a special line
type, it may happen that the result of 'postscript()' is not readable by
ghostview (which may not be an R error, thus not bug report ;-).
This is the case when mixing lty as 0:6 and character or even when
using lty as character only.
Example:
postscript("test.ps")
plot(1:10,
2002 Dec 09
2
APL?
Hi,
is anybody out there who knows APL and would help me to translate 52
lines of APL code into propper R?
best,
Torsten
2004 Mar 03
2
read.spss and time/date information
I don't use SPSS but following through on your detective work
can provide the likely answer.
First note that both date numbers are evenly divisible by the number
of seconds in a day, i.e. 24*60*60. This suggests that these numbers
are seconds since some origin.
Since we know "2003/02/11" corresponds to 13264300800 we deduce that
the origin must be
spss.orig <-
2002 Oct 17
3
Non-central distributions
Hi Folks,
I note that, while the "chisq" functions
dchisq(x, df, ncp=0, log = FALSE)
pchisq(q, df, ncp=0, lower.tail = TRUE, log.p = FALSE)
qchisq(p, df, ncp=0, lower.tail = TRUE, log.p = FALSE)
rchisq(n, df, ncp=0)
all have a slot for the non-centrality parameter "ncp", of
the functions for the t and F distributions:
dt(x, df, log = FALSE)
2004 Apr 26
1
Segfault: .Call and classes with logical slots
Hi,
the following example aiming at a class containing a logical slot
segfaults under R-1.9.0 when `gctorture(on = TRUE)' is used:
Code code (dummy.c):
#include <Rdefines.h>
SEXP foo() {
SEXP ans;
PROTECT(ans = NEW_OBJECT(MAKE_CLASS("test")));
SET_SLOT(ans, install("lgl"), allocVector(LGLSXP, 1));
LOGICAL(GET_SLOT(ans,
2006 Dec 19
3
Bug in rt() ? (PR#9422)
-----BEGIN PGP SIGNED MESSAGE-----
Hash: SHA1
<<insert bug report here>>
Reproduced on Debian and Windows ...
On 2.4.x if you execute
set.seed(12345)
t.1 <- rt(n = 1000, df = 20)
set.seed(12345)
t.2 <- rt(n = 1000, df = 20, ncp = 0)
all.equal(t.1, t.2) ## Not close to true
This appears to be due to the fact that in 2.4.x rt is now
rt
function (n, df, ncp = 0)
{
if
2004 Mar 12
1
plot.dendrogram and expressions
Hi,
currently the "label" and "edgetext" attributes of a dendrogram are
coerced to character before they are added to a plot with `text'. Is there
a specific reason to do so (expect for the determination of the size of
the character string to be plotted)? Otherwise one could plot the
attributes directly via
diff dendrogram.R /usr/src/R/src/library/stats/R/dendrogram.R
2005 Jan 25
4
typo in ?NotYetImplemented
The `examples' section says
plot.mlm # to see how the "NotYetImplemented"
# reference is made automagically
^
Best,
Torsten
2001 Oct 18
1
vectors / matrices
Hi,
a friend of mine came across this
R> x <- 1:5
R> cbind(x,x)
x x
[1,] 1 1
[2,] 2 2
[3,] 3 3
[4,] 4 4
[5,] 5 5
R> rbind(x,x)
[,1] [,2] [,3] [,4] [,5]
x 1 2 3 4 5
x 1 2 3 4 5
x is a vector and therefore has no dim-attribute. Obviously cbind treats x
as a col-vector but rbind treats x as a row-vector, that is: two
functions have a different
2005 Nov 14
1
effect sizes for Wilcoxon tests
Hello,
I use t.test for normal distributed and wilcox.test for non-normal
distributed samples.
It is easy to write a function for t.test that calculates the effect
size, because all parts of the formula are available from the t.test
result: r = sqrt(t*t / (t*t + df))
However, for Wilcoxon tests, the formula for effect sizes is:
r = Z / sqrt(N)
I wonder how I can calculate the Z-score in R for
2003 Sep 16
1
`var' broken in 1.8.0 alpha (2003-09-15)
Hi,
in last nights alpha version, `var' is broken:
R> var(rnorm(100))
Error in var(rnorm(100)) : 3 arguments passed to "cov" which requires 4.
which I suspect is due to recent changes to `cov'. The same is true for
R> cov(rnorm(100), rnorm(100))
Error in cov(rnorm(100), rnorm(100)) : 3 arguments passed to "cov" which
requires 4.
Best,
Torsten
R> version
2000 Dec 12
1
r-sync down?
torsten@www:/raid/home/torsten > ping rsync.r-project.org
PING franz.stat.wisc.edu (128.105.174.95): 56 data bytes
--- franz.stat.wisc.edu ping statistics ---
12 packets transmitted, 0 packets received, 100% packet loss
Torsten
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2006 Apr 24
3
gsub + backslashes
Dear developeRs,
I thought that backslashes can be escaped in the usual way (and I think I
did this before) but I can't see why
R> gsub("\\", "x", "\alpha")
Error in gsub(pattern, replacement, x, ignore.case, extended, fixed,
useBytes) :
invalid regular expression '\'
gives an error. Or am I just blind?
Best,
Torsten
R> version