Displaying 20 results from an estimated 2000 matches similar to: "Re : CDF of a Multivariate Normal"
2002 Jan 23
6
multivariate simulation
To whom it may concern,
I try to simulate a non-normal multivariate distribution. The MASS package
allows by mean of "mvrnorm" command to perform a multivariate normal
simulation. Is there an equivalent command for an arbitrary multivariate
distribution available in the R-language?
Thank you in advance.
Bernard Colin
Colin Bernard
Professeur titulaire
D?partement de Math?matiques et
2002 Dec 09
0
Re : Information
To whom it may concern,
For a sample (xi,yi) i=1,2,...,n of a bivariate normal vector (X,Y), I have
to evaluate ( for some simulation) the cumulative distribution function of
(X,Y) at each point (xi,yi) and I have not find in R a package that evaluate
this function. Is there a such package in R? If no, how can I do to make my
simulation succesful?
Thank you very much for your assistance.
2005 Mar 02
1
Applying a function to all combinations of factors
Is there a way to apply a function, say cor(), to each combination of some
number of variables, and this, without using loops?
For example, I have day, hour, var1 and var2. How could I compute
cor(var1,var2) for each day*hour combination and obtain a matrix with day,
hour and the cor value for each combination?
Thanks for your time,
Marc
===================
Marc Bélisle
Professeur adjoint
2006 Jun 02
1
Multivariate skew-t cdf
Dear All,
I am using the pmst function from the sn package (version 0.4-0). After
inserting the example from the help page, I get non-trivial answers, so
everything is fine. However, when I try to extend it to higher dimension:
xi <- alpha <- x <- rep(0,27)
Omega <- diag(0,27)
p1 <- pmst(x, xi, Omega, alpha, df = 5)
I get the following result:
>p1
[1] 0
attr(,"error")
2008 Jan 29
0
number of rescaling cycles in decorana
How do one dertermine the optimal number of rescaling cycles to use when
performing DCA using the decorana function (library vegan)?
Thanks for your time,
Marc
===================
Marc Bélisle
Professeur adjoint
Chaire de recherche du Canada en écologie spatiale et en écologie du paysage
Département de biologie
Université de Sherbrooke
2500 Boul. de l'Université
Sherbrooke, Québec
J1K 2R1
2003 Oct 31
4
dnorm() lead to a probability >1
Howdee,
One of my student spotted something I can't explain: a probability >1 vs a
normal probability density function.
> dnorm(x=1, mean=1, sd=0.4)
[1] 0.9973557
> dnorm(x=1, mean=1, sd=0.39)
[1] 1.022929
> dnorm(x=1, mean=1, sd=0.3)
[1] 1.329808
> dnorm(x=1, mean=1, sd=0.1)
[1] 3.989423
> dnorm(x=1, mean=1, sd=0.01)
[1] 39.89423
> dnorm(x=1, mean=1, sd=0.001)
[1]
2008 Feb 18
2
skip non-converging nls() in a list
Howdee,
My question appears at #6 below:
1. I want to model the growth of each of a large number of individuals using
a 4-parameter logistic growth curve.
2. nlme does not converge with the random structure that I want to use.
3. nlsList does not converge for some individuals.
4. I decided to go around nlsList using:
t(sapply(split(data, list(data$id)),
function(subd){coef(nls(mass ~
2008 Feb 15
2
lmList, tapply() and lm()
Howdee,
*** I know that the lmList() function exists, yet I don't want to use it.
***
Would anyone be kind enough to tell how I can apply the function lm() to
each level of a given factor so to obtain the intercept and slope for each
factor level within a matrix?
For instance, suppose a dataframe containing 3 variables: id, x and y.
I want to compute the function lm() for each level
2020 Jun 26
1
"R CMD Sweave --driver=..." woes
In trying to change the driver used by Sweave on the command line using
R CMD Sweave --driver=foo
I consistently get the "directory 'foo' does not exist' error. (For any value of 'foo', even the default 'RweaveLatex'.)
Looking up the source code for function .Sweave that is called by 'R CMD Sweave', I notice that the argument 'driver', if
2008 Feb 19
0
nlsList - Error in !unlist(lapply(coefs, is.null))
Howdee,
I am able to fit a 4-parameter logistic growth curve to a dataset which
comprise many individuals (using R v. 2.3.1). Yet, if I want to obtain the
parameters for each individual (i.e., for each 'id') using nlsList, then I
obtain an Error message which I have trouble interpreting. Any advice as to
how I can solve this problem?
Thanks for your time,
Marc
> reg <-nls(mass ~
2009 Jun 05
3
from 3 numeric variables to a string
Hi there,
I have 3 numeric variables: day (e.g., 05), month (e.g., 06), year (e.g.,
2009).
I would like to create a (string) variable of the following form:
month/day/year (e.g., 06/05/2009).
I would be grateful to anyone who could point me toward a solution.
Sincerely,
Marc
===================
Marc B?lisle
Professeur agr?g?
Chaire de recherche du Canada en ?cologie spatiale et en ?cologie
2004 Apr 26
2
mixed model with binomial link?
Hello. I have to fit a mixed model from a repeated measures split-plot
experiment in which the response variable is binary. This requires a
generalised linear mixed model in which I can specify a binomial
distribution. I can’t find the appropriate package in R. I have looked
at glmmML, but it doesn’t seem to allow any mixed structure beyond a
simple 2-level one. Can anyone point me to the
2004 Sep 30
1
histograms with more than one variable
Hello. I want to plot the distribution of a continuous variable (y) in
each of two groups on the same graph as histograms. I suppose one could
call this a 2-d histogram? Can this be done in R? Here is a typical
data.set:
y group
1.2 1
3.3 1
2.4 2
5.7 1
0.2 2
etc.
Bill Shipley
Subject Matter Editor, Ecology
North American Editor, Annals of
2006 Apr 13
1
obtaining residuals from lmer
Hello. I cannot find out how to extract the residuals from a mixed model
using the lmer function. Can someone help?
Bill Shipley
North American Editor, Annals of Botany
Editor, "Population and Community Biology" series, Springer Publishing
Département de biologie, Université de Sherbrooke,
Sherbrooke (Québec) J1K 2R1 CANADA
Bill.Shipley@USherbrooke.ca
2016 Nov 14
0
Major update of package actuar
Dear useRs,
I'm happy to announce a substantial update of package actuar that bumps the version number to 2.0-0. This release focuses on additional support for continuous and discrete distributions, new functions to simulate data from compound models and mixtures, and revised and improved documentation.
A slightly shortened version of the NEWS file follows:
NEW FEATURES
? Support for the
2016 Nov 14
0
Major update of package actuar
Dear useRs,
I'm happy to announce a substantial update of package actuar that bumps the version number to 2.0-0. This release focuses on additional support for continuous and discrete distributions, new functions to simulate data from compound models and mixtures, and revised and improved documentation.
A slightly shortened version of the NEWS file follows:
NEW FEATURES
? Support for the
2006 Feb 16
1
help downloading lme4 from CRAN
Hello. I am having trouble downloading the lme4 package from the CRAN
site. The error is:
> local({a <- CRAN.packages()
+ install.packages(select.list(a[,1],,TRUE), .libPaths()[1],
available=a, dependencies=TRUE)})
trying URL `http://cran.r-project.org/bin/windows/contrib/2.0/PACKAGES'
Content type `text/plain; charset=iso-8859-1' length 26129 bytes
opened URL
downloaded 25Kb
2003 Oct 28
1
setting up complicated ANOVA in R
Hello. I am about to do a rather complicated analysis and am not sure
how to do it. The experiment has a split-plot design and also repeated
measures. Both of these complications require one to define an error
term and it seems that one cannot specify two such terms. The
split-plot command is:
aov(y~covariates +A*B+Error(C), data=) where A and B are the fixed
effects and C is the
2004 Apr 01
1
nls function
Hello. I am trying to fit a non-rectangular hyperbola function to data
of photosynthetic rate vs. light intensity. There are 4 parameters that
have to be estimated. I find the nls function very difficult to use
because it often fails to converge and then gives out cryptic error
messages. I have tried playing with the control parameters but this
does not always help.
Is there another
2005 Jan 05
1
cubic spline smoother with heterogeneous variance.
Hello. I want to estimate the predicted values and standard errors of
Y=f(t) and its first derivative at each unique value of t using the
smooth.spline function. However, the data (plant growth as a function
of time) show substantial heterogeneity of variance since the variance
of plant mass increases over time. What is the consequence of such
heterogeneity of variance in terms of bias in the