Displaying 15 results from an estimated 15 matches for "waldweg".
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landweg
2008 Nov 06
2
replacing characters in formulae / models
...ot; by "w" in the formula object "y".
How can this be done? Somehow, the methods that can be used in character objects do not work 1:1 in
formula objects...
Many thanks and best wishes
Christoph
--
Dr. rer.nat. Christoph Scherber
University of Goettingen
DNPW, Agroecology
Waldweg 26
D-37073 Goettingen
Germany
phone +49 (0)551 39 8807
fax +49 (0)551 39 8806
Homepage http://www.gwdg.de/~cscherb1
2007 Nov 08
6
Extract correlations from a matrix
...ow do I extract only those correlations that are >0.6?
w[w>0.6] #obviously doesn?t work,
and I can?t find a way around it.
I would very much appreciate any help!
Best wishes
Christoph
(using R 2.5.1 on Windows XP)
--
Dr. Christoph Scherber
DNPW, Agroecology
University of Goettingen
Waldweg 26
D-37073 Goettingen
Germany
phone +49(0)551 39 8807
fax +49(0)551 39 8806
homepage www.gwdg.de/~cscherb1
2008 Feb 22
3
Simultaneously summarizing many models
...? I guess I would need to use expression() or substitute() but I don?t
know how to construct m1, m2... without the quotation marks.
Thanks very much for your help!
Best wishes,
Christoph
(using R 2.5.1 on Windows XP SP2)
--
Dr. Christoph Scherber
DNPW, Agroecology
University of Goettingen
Waldweg 26
D-37073 Goettingen
Germany
phone +49(0)551 39 8807
fax +49(0)551 39 8806
homepage www.gwdg.de/~cscherb1
2008 Nov 25
4
glm or transformation of the response?
...ould be your recommendation to the students,
given the fact that most of the standard glm models obviously don?t seem to produce good fits here?
Many thanks and best wishes
Christoph
(using R 2.8.0 on Windows XP)
--
Dr. rer.nat. Christoph Scherber
University of Goettingen
DNPW, Agroecology
Waldweg 26
D-37073 Goettingen
Germany
phone +49 (0)551 39 8807
fax +49 (0)551 39 8806
Homepage http://www.gwdg.de/~cscherb1
2009 Aug 20
1
nested, repeated measure lme
...d that (2) is the only approach that works. But how could I then still include the nesting information from (1)?
Many thanks for your help!
Best wishes
Christoph
(using R 2.9.0 and the nlme library on Windows XP)
--
Dr. rer.nat. Christoph Scherber
University of Goettingen
DNPW, Agroecology
Waldweg 26
D-37073 Goettingen
Germany
phone +49 (0)551 39 8807
fax +49 (0)551 39 8806
Homepage http://www.gwdg.de/~cscherb1
2008 Jun 07
1
Multivariate LM: calculating F-values after calling linear.hypothesis
...uck with; I thought using
diag() on the SSPH and SSPE matrices should give me the sums of squares
for hypothesis and error; so division should yield the F values?
I would be most grateful for any help!
Best wishes
Christoph
--
Dr. Christoph Scherber
University of Goettingen
DNPW, Agroecology
Waldweg 26
D-37073 Goettingen, Germany
www.gwdg.de/~cscherb1
2007 May 07
4
Mardia's multivariate normality test
Dear all,
I got this error message
> library(dprep)
> mardia(Savg)
Error in cov(data) : 'x' is empty
But with the same data, I got
> library(mvnormtest)
> mshapiro.test(Savg)
Shapiro-Wilk normality test
data: Z
W = 0.9411, p-value = 0.6739
What does the error message "Error in cov(data) : 'x' is empty" mean? Thanks a lot!
Jiao
2008 Oct 01
0
Minimizing both AIC and df in model selection
...e sensible, then, to choose the best-fit model as the one that has *both* minimal AIC
*and* minimal number of d.f.?
Are there any references for such an approach?
Many thanks for your help!
Best wishes,
Christoph
--
Dr. rer.nat. Christoph Scherber
University of Goettingen
DNPW, Agroecology
Waldweg 26
D-37073 Goettingen
Germany
phone +49 (0)551 39 8807
fax +49 (0)551 39 8806
Homepage http://www.gwdg.de/~cscherb1
2008 Oct 02
1
An AIC model selection question
...other models.
Would it be allowed to select model3 instead, simply because it uses up less df and the delta-AIC
between model2 and model3 is just 1?
Many thanks for any suggestions/comments!
Best wishes
Christoph
--
Dr. rer.nat. Christoph Scherber
University of Goettingen
DNPW, Agroecology
Waldweg 26
D-37073 Goettingen
Germany
phone +49 (0)551 39 8807
fax +49 (0)551 39 8806
Homepage http://www.gwdg.de/~cscherb1
2008 Nov 03
2
standard errors for predict.nls?
Dear all,
Is there a way to retrieve standard errors from nls models? The help page tells me that arguments
such as se.fit are ignored...
Many thanks and best wishes
Christoph
--
Dr. rer.nat. Christoph Scherber
University of Goettingen
DNPW, Agroecology
Waldweg 26
D-37073 Goettingen
Germany
phone +49 (0)551 39 8807
fax +49 (0)551 39 8806
Homepage http://www.gwdg.de/~cscherb1
2008 Aug 22
1
lme questions re: repeated measures & covariance structure
Hello,
We are attempting to use nlme to fit a linear mixed model to explain bird
abundance as a function of habitat:
lme(abundance~habitat-1,data=data,method="ML",random=~1|sampleunit)
The data consist of repeated counts of birds in sample units across multiple
years, and we have two questions:
1) Is it necessary (and, if so, how) to specify the repeated measure
(years)? As written,
2009 Jan 07
1
Extracting degrees of freedom from a gnls object
...t the total and residual d.f. from a gnls object?
I have tried str(summary(gnls.model)) and str(gnls.model) as well as gnls(), but couldn?t find the
entry in the resulting lists.
Many thanks!
Best wishes
Christoph
--
Dr. rer.nat. Christoph Scherber
University of Goettingen
DNPW, Agroecology
Waldweg 26
D-37073 Goettingen
Germany
phone +49 (0)551 39 8807
fax +49 (0)551 39 8806
Homepage http://www.gwdg.de/~cscherb1
2008 Jul 03
1
lm() question
I have data that looks like
YC Age Num
82 11 2
83 10 0
84 9 8
85 8 21
86 7 49
87 6 18
88 5 79
89 4 28
90 3 273
91 2 175
with a program
mod1=lm(log(Num+1)~YC, data=box44)
plot(log(Num+1)~YC, data=box44, pch=19, xlab="Year Class",
ylab="Loge Number at age", ylim=c(0,6), xlim=c(91,82))
abline(lm(log(Num+1)~YC), col="blue", lwd=2)
summary(mod1)
I need to
2008 Jul 24
2
What is wrong with this contrast matrix?
...how can I assess if the matrix is orthogonal (given that it is non-symmetrical,
hence det(P) and other matrix operations won?t work)
Many thanks for your help!
Best wishes
Christoph.
(using R 2.7.1 on Windows XP)
--
Dr. rer.nat. Christoph Scherber
University of Goettingen
DNPW, Agroecology
Waldweg 26
D-37073 Goettingen
Germany
phone +49 (0)551 39 8807
fax +49 (0)551 39 8806
Homepage http://www.gwdg.de/~cscherb1
2005 Feb 09
6
randomisation
Dear useRs
I am looking for a way to randomise the values within a matrix:
the conditions are that the sums of the rows and the sums of the columns should
remain the same as in the original matrix.
Any help would be appreciated
Cheers
Yann