Displaying 20 results from an estimated 5000 matches similar to: "GAMs with errors in covariates"
2007 Aug 14
1
weights in GAMs (package mgcv)
Dear list,
I?m using the ?mgcv? package to fit some GAMs. Some of my covariates are
derived quantities and have an associated standard error, so I would
like to incorporate this uncertainty into the GAM estimation process.
Ideally, during the estimation process less importance would be given to
observations whose covariates have high standard errors.
The gam() function in the ?mgcv? package
2006 Oct 20
2
Recursive decreasing sequences
Hello fellow R's,
I'm sure there must be an easy way to do this. But after digging in the
documentation and thinking about it for a while I couldn't figure it
out. I need to get a decreasing recursive vector in. I mean something
like this: if starting at 2, and ending at 6, the vector should be
2 3 4 5 6 3 4 5 6 4 5 6 5 6 6
An easy way would be to do this
x <-
2007 Jun 21
1
mgcv: lowest estimated degrees of freedom
Dear list,
I do apologize if these are basic questions. I am fitting some GAM
models using the mgcv package and following the model selection criteria
proposed by Wood and Augustin (2002, Ecol. Model. 157, p. 157-177). One
criterion to decide if a term should be dropped from a model is if the
estimated degrees of freedom (EDF) for the term are close to their lower
limit.
What would be the
2005 Nov 09
2
Variograms and large distances
Hello R list,
I need to compute empirical variograms using data from a large
geographic area (~10^6 km2). Although I could not find a specific
reference, I assume that both geoR and gstat calculate distances among
data points assuming points are on a flat surface (using the Pythagorean
Theorem). Because the location of my data is large and located near the
pole, assuming that latitude and
2006 Jun 23
1
Running executable files from R
Hello fellow R's,
I apologize if this question was answer elsewhere. I have an executable
file that I need to run from R. Basically I want to use R to create the
input files this executable requires, then run it, and finally use R
again to analyze the output files. Because I have to do this many times
I'd like to have the R code call the executable file after the input
files are
2007 Jul 20
3
SOS
Dear all, I am a new user of R. I would like to know how to get fund's returns in percentage (%). For example, I use: R <- ts(read.xls("FundData"), frequency = 12, start = c(1996, 1)) Whith this program, the returns are like 0.0152699. But, I would like to have 1.52%. Please advise me about the function. Thanks! Fabrice
2011 Feb 28
1
sub setting data.frame
Hi All,
I have a data.frame:
>pop
consumed ind recruits gonad cell
1 516.74 1 0.02 20.21 0.25
2 1143.20 1 0.02 20.21 0.50
3 250.00 1 0.02 20.21 0.25
4 251.98 1 0.02 18.69 0.25
5 598.08 1 0.02 18.69 0.25
6 437.38 1 0.02 18.69 0.25
7 250.00 1 0.02 17.39 0.25
8 250.00 1 0.02 17.39 0.25
9
2007 Nov 14
2
About print a label in plot
Dear list,
Hello! I have a question about how to print a label in the plot.
I am using the following code:
<pdf("mel4_chr3_11cancer_cghFLasso.pdf", height=6,
width=5);plot(Disease.FL, index=i, type="Single",main="Plot of
Labels");dev.off();
But "Plot of Labels" has not been printed. Any suggestions?
Thanks a lot!
Allen
2011 Jan 26
0
post-hoc comparisons in GAMs (mgcv) with parametric terms
Dear list,
I?m wondering if there is something analogous to the TukeyHSD function
that could be used for parametric terms in a GAM. I?m using the mgcv
package to fit models that have some continuous predictors (modeled as
smooth terms) and a single categorical predictor. I would like to do
post hoc test on the categorical predictor in the models where it is
significant.
Any suggestions?
2007 Aug 30
4
How to measure mode (central tendancy)
What is the name of the function to give me the mode (central tendancy) of a
numeric variable that can be negative?
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2007 Apr 08
1
Relative GCV - poisson and negbin GAMs (mgcv)
I am using gam in mgcv (1.3-22) and trying to use gcv to help with model selection. However, I'm a little confused by the process of assessing GCV scores based on their magnitude (or on relative changes in magnitude).
Differences in GCV scores often seem "obvious" with my poisson gams but with negative binomial, the decision seems less clear.
My data represent a similar pattern as
2007 Dec 14
1
detailed calculation of two way anova with unbalanced design
Dear list,
Could someone show me where can I find the detailed formula on how to
calculate the two way anova with unbalanced design? Say, if I have 2*2
design with 10,20,30,40 samples in each of the 2*2 cells. Most of the places
I've googled only show how to calculate using software such as R, but not
clear the detailed formula for calculating this.
Thanks,
Jack
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2007 Aug 07
2
Spatial sampling problem
Hi All,
I am new in R and trying to simulate random normal 2D field with mean trend say north-south. My domain is 10x10 grid and I am trying to use mvnorm but do not know how to specify the domain and the mean field.
I would appreciate any help.
Cheers, SK
---------------------------------
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2008 May 29
2
Plot colors
Hi. I am plotting graphs for values ranging between -1 and 10, for example:
(1,2,1,1,6,7,-1,-1,5,-1)
I am trying to plot the graphs so that the points with value of -1 will be
in one specific color, and the rest of the points will be in one different
specific color. I would be grateful for any idea of how to do that in two
colors.
Thanks for any hint.
--
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2007 Aug 14
2
labelling plots with ancillary data in data.frame
Hi All,
I am busy using R to do some regression modelling and have been using plot(x,y,"") to visualise my variables. I would now like to label my points using data stored in the data.frame used for the regression analysis. For example each of my data points is made up of a field measured forest volume value and a remotely sensed vegetation estimate (NDVI). Each point is an enumeration
2007 Dec 07
4
if/else for plot/lines?
I'm interested in writing a function that constructs a new plot on the
current graphics device if no plot exists there yet, but adds lines to
the existing plot if a plot is already there. How can I do this? It
seems to me that the exists() function might be co-opted to do this, but
it's not obvious how.
Many thanks,
Roger
--
Roger Levy Email: rlevy at ucsd.edu
2007 Jul 18
3
How to open an URL using RGtk2
Hi
I am working on R 2.5.0 on window. I am trying to provide a Hyper-link to
the user as a result, I have tried using gtkLinkButton to exercise the
facility, however, i am not able to perform the required task, i.e. when I
clicked on the LinkButton actually nothing happened.
I have gone through the documentation for the same and found that
GtkLinkButtonUriFunc is a function which is require to
2010 Feb 15
1
GAM for non-integer proportions
Dear list,
I´m using the mgcv package to model the proportion by weight of certain prey
on the stomach content of a predator. This proportion is the ratio of two
weights (prey weight over stomach weight), and ranges between 0 and 1. The
variance is low when proportion is close to 0 and 1, and higher at
intermediate values.
It seems that the best way to go is to model this using the
2011 Mar 11
0
variance explained by each term in a GAM
Picking up an ancient thread (from Oct 2007), I have a somewhat more complex
problem than given in Simon Wood's example below. My full model has more than
two smooths as well as factor variables as in this simplified example:
b <- gam(y~fv1+s(x1)+s(x2)+s(x3))
Judging from Simon's example, my guess is to fit reduced models to get
components of deviance as follows:
b1 <-
2010 May 20
1
Strange behaviour when using diff with POSIXt and POSIXlt objects
Dear list,
I´m calculating time differences between series of time stamps and I noticed
something odd:
If I do this...
> time1=strptime("2009 05 31 22 57 00",format="%Y %m %d %H %M")
> time2=strptime("2009 05 31 23 07 00",format="%Y %m %d %H %M")
>
> diff(c(time1,time2),units="mins")
Time difference of 10 mins
.. I get the correct