Displaying 20 results from an estimated 1000 matches similar to: "Statistical test for heteroscedasticity for an object of class "gls""
2012 Sep 24
3
List creation based on matrix
Hi guys,
It would be great if you could help me with this one...
I'm looking to create a script to convert a matrix of species abundance e.g:
<http://r.789695.n4.nabble.com/file/n4643978/species_matrix.jpg>
into two vectors e.g:
<http://r.789695.n4.nabble.com/file/n4643978/communitylist.jpg>
----------------
If you feel there is no easy answer to this and that it would be
2012 Sep 24
6
Script to count unique values from two linked matricies
I hope you can help with this one.
I have two matricies:
1. A species abundance matrix:
<http://r.789695.n4.nabble.com/file/n4643979/2species_matrix.jpg>
2. A species trait score matrix:
<http://r.789695.n4.nabble.com/file/n4643979/2trait_matrix.jpg>
The trait matrix lists trait scores for each species as listed in the
species abundance matrix.
I would like to create a script
2013 Jan 15
5
Code to fetch summary info from vector
Hi all,
Thanks in advance for any help.
I have a vector "b":
b=c(1,1,1,2,3,4,3,2,1,1,1,1,1,2,3,4,5,4,3.5,3,2,1,1,1)
Imagine b is river flow throughout time.
I would like some code that will generate the following information:
number of individual 'periods' where b>1 (= 2 in this case)
period 1 length = 5, max = 4
period 2 length = 8, max = 5
I can't figure anything
2013 Feb 04
6
Script for conditional sums of vectors
Hi guys,
I hope you can help me with this (probably) simple query:
I have a data frame:
--------------------------
a=c(1,1,1,1,1,1,2,2,2,2,2,2)
b=c(1,1,1,2,3,4,1,1,2,2,3,4)
c=c(400,200,300,100,500,300,200,100,500,400,200,100)
data=data.frame(a=a,b=b,c=c)
--------------------------
And I would like to get the following output:
--------------------------
b
a 1 2 3 4
1 900 100 500 300
2
2013 Mar 18
3
Superscript followed by number then superscript in text
Hi all,
I'm having problems finding the correct format for a command.
I would like to write some text on a plot.
I'm using the following command:
text(x,y,"text here", srt=90)
I would like the text to read:
capacity 10^3 m^3
(with ^ denoting superscript (i.e. each '3' as superscript).
I've tried fiddling around with expression(paste(etc.... to no avail. I
2007 Nov 27
1
Difference between AIC in GLM and GLS - not an R question
Hi,
I have fitted a model using a glm() approach and using a gls() approach
(but without correcting for spatially autocorrelated errors). I have
noticed that although these models are the same (as they should be), the
AIC value differs between glm() and gls(). Can anyone tell me why they
differ?
Thanks,
Geertje
~~~~
Geertje van der Heijden
PhD student
Tropical Ecology
School of Geography
2004 Sep 07
6
Further png() question
Ok, I have reinstalled R-1.9.0 and this appears to have fixed the
problems I was having with png(). However, I have a further question
regarding png()
Is it possible to pass a par() argument to the png() command? I am
wanting to produce 4 plots per object, which I normally acheive on an X
window by par(mfrow=c(1,4)). I have tried calling a new plot and setting
par in this way but this has no
2006 Jan 27
2
How do I "normalise" a power spectral density analysis?
Hi everyone
Can anyone tell me how I normalise a power spectral density (PSD) plot of a
periodical time-series. At present I get the graphical output of spectrum VS
frequency.
What I want to acheive is period VS spectrum? Are these the same things but the
x-axis scale needs transformed ?
Any help would be greatly appreciated
Tom
2005 Feb 16
4
Passing colnames to graphics title
Hi,
Just a quick query - if I'm creating a function to produce a number of
histograms per page of output (one per column from a matrix), how can I
pass the column name of the matrix into the title (or indeed to form part
of the x-axis label)?
TIA,
Laura
Laura Quinn
Institute of Atmospheric Science
School of Earth and Environment
University of Leeds
Leeds
LS2 9JT
tel: +44 113 343 1596
fax:
2006 Jan 28
3
Creating 3D Gaussian Plot
Hello,
I requested help a couple of weeks ago creating a dipole field in R but
receieved no responses. Eventually I opted to create a 3d sinusoidal plot
and concatenate this with its inverse as a means for a "next best"
situation. It seems that this isn't sufficient for my needs and I'm really
after creating a continuous 3d gaussian mesh with a "positive" and
2003 Mar 14
0
gls with "crossed heteroscedasticity"
Dear All,
I am using the function gls (in the nlme package) and I would like to fit a
heteroscedastic model, with different variances for each of the levels of two
stratification variables.
In p. 210 of Pinheiro & Bates ("Mixed effects models in S and S-Plus", 2000,
Springer), the authors show the use of the "*" operator. However, that is not
what I want, because it
2004 Aug 15
3
Stacking Vectors/Dataframes
Hello,
Is there a simple way of stacking/merging two dataframes in R? I want to
stack them piece-wise, not simply add one whole dataframe to the bottom of
the other. I want to create as follows:
x.frame:
aX1 bX1 cX1 ... zX1
aX2 bX2 cX2 ... zX2
... ... ... ... ...
aX99 bX99 cX99 ... zX99
y.frame:
aY1 bY1 cY1 ... zY1
aY2 bY2 cY2 ... zY2
... ... ... ... ...
aY99 bY99 cY99 ...
2009 Apr 04
1
Problem with sample()
Hi,
I'm having a problem using sample() within a function.
Basically I get an error reading:
Error in sample(v, 1, prob = h) : non-positive probability
Can anyone advise me as to the possible origin of this error?
Here is my code
#Discretised Gillespie algorithm function (From SMfSB, D.J. Wilkinson)
gillespied=function (N, T=100, dt=1, ...)
{
tt=0
n=T%/%dt
x=N$M
2006 Feb 08
2
slightly off-topic re prcomp()
Hi,
I was wondering if anyone could tell me why prcomp() will "Invent" modes
of variation in a PCA on identical replicates of data? I would have
expected 50 (or whatever number) of identical replicates to return a null
score in such an analysis (or at the least, all variables would share the
same PC score). This is not the case and I was wondering could someone
point me in the direction
2016 Jul 07
19
[Bug 96836] New: Kernel unaligned access at TPC[105d9fb4] nvkm_instobj_wr32+0x14/0x20
https://bugs.freedesktop.org/show_bug.cgi?id=96836
Bug ID: 96836
Summary: Kernel unaligned access at TPC[105d9fb4]
nvkm_instobj_wr32+0x14/0x20 [nouveau]
Product: xorg
Version: unspecified
Hardware: SPARC
OS: Linux (All)
Status: NEW
Severity: normal
Priority: medium
2017 Aug 16
4
{nlme} Question about modeling Level two heteroscedasticity in HLM
Hello dear uesRs,
I am working on modeling both level one and level two
heteroscedasticity in HLM. In my model, both error variance and
variance of random intercept / random slope are affected by some level
two variables.
I found that nlme is able to model heteroscedasticity. I learned how
to use it for level one heteroscedasticity but don't know how to use
it to model the level
2005 Feb 02
2
Runnning R remotely
Hi,
I was wondering if anyone might be able to help. I am trying to run R on a
remote machine, part of the model run I am attempting writes an external
file output as a png (about 48 iterations per model run). I am running R
1.9.1 on SuSe9.0, and am accessing this via ssh from a Debian machine.
Initially I used the command ssh -X IP.address and whilst I was able to
run the model successfully the
2008 Sep 04
2
Correct for heteroscedasticity using car package
Dear all,
Sorry if this is too obvious.
I am trying to fit my multiple regression model using lm()
Before starting model simplification using step() I checked whether the
model presented heteroscedasticity with ncv.test() from the CAR package.
It presents it.
I want to correct for it, I used hccm() from the CAR package as well and
got the Heteroscedasticity-Corrected Covariance Matrix.
I am not
2017 Aug 16
0
{nlme} Question about modeling Level two heteroscedasticity in HLM
If you don't get a response it is because you did not read the Posting Guide which indicates that the R-sig-ME mailing list is where this question would have been on-topic.
--
Sent from my phone. Please excuse my brevity.
On August 16, 2017 6:17:03 AM PDT, b88207001 at ntu.edu.tw wrote:
>Hello dear uesRs,
>
>I am working on modeling both level one and level two
2017 Aug 16
0
{nlme} Question about modeling Level two heteroscedasticity in HLM
A better place for this post would be on R's mixed models list:
r-sig-mixed-models .
Cheers,
Bert
Bert Gunter
"The trouble with having an open mind is that people keep coming along
and sticking things into it."
-- Opus (aka Berkeley Breathed in his "Bloom County" comic strip )
On Wed, Aug 16, 2017 at 6:17 AM, <b88207001 at ntu.edu.tw> wrote:
> Hello dear