Displaying 20 results from an estimated 10000 matches similar to: "Density Estimation"
2001 May 10
3
lookup function for density(...) objects
Hi folks:
Is there a lookup function that returns the variate given the cumulative
probability for an object returned by the density(...) function?
> mydata _ as.vector(mymatrix)
> mydata.density _ density(mydata)
> mydata.p80 _ lookup(mydata.density, p=0.8) # is there any function to
accomplish this task?
Thanks.
Rajiv.
--------
Rajiv Prasad, Postdoctoral Research Associate,
2004 Nov 13
3
density estimation: compute sum(value * probability) for given distribution
Dear R users,
This is a KDE beginner's question.
I have this distribution:
> length(cap)
[1] 200
> summary(cap)
Min. 1st Qu. Median Mean 3rd Qu. Max.
459.9 802.3 991.6 1066.0 1242.0 2382.0
I need to compute the sum of the values times their probability of
occurence.
The graph is fine,
den <- density(cap, from=min(cap),
to=max(cap), give.Rkern=F)
2006 Jun 07
4
Density Estimation
Dear R-list,
I have made a simple kernel density estimation by
x <- c(2,1,3,2,3,0,4,5,10,11,12,11,10)
kde <- density(x,n=100)
Now I would like to know the estimated probability that a
new observation falls into the interval 0<x<3.
How can I integrate over the corresponding interval?
In several R-packages for kernel density estimation I did
not found a corresponding function. I
2003 Oct 22
1
2 D non-parametric density estimation
I have spatial data in 2 dimensions - say (x,y). The correlation
between x and y is fairly substantial. My goal is to use a
non-parametric approach to estimate the multivariate density describing
the spatial locations. Ultimately, I would like to use this estimated
density to determine the area associated with a 95% probability contour
for the data.
Given the strong correlation between x and
2008 Apr 23
1
Density estimation
Hi,
I am analysing a dataset containing genetic distances within and between
species. I want to show a overlap of the distributions of the intra- and
interspecific values; on a second graph I use a cut-off value to determine
these boundaries. As the dataset contains >30 000 values, I would like to do
this with a simple line rather than superimposed histograms. Hence, density
plots. With
2009 Mar 25
1
Density estimation: scale back for calendar time
Dear all:Request your indulgence. The econophysics gurus do this stuff all
the time: all their PDFs are smooth, with neat log x axis.
1. The kernel density estimate (KDE) function returns the empirical
probability density at 2^n points (min: 512). The big question is how do I
scale back the x-values (say, density$x) to x-values in terms of the
original dataset?
2. To give you a concrete idea, i
2002 Jul 29
1
density estimation on 2-D bounded domain
Dear R experts,
density estimation on a 2 dimensional bounded domain
---------------------------------------------------------------------
I am currently trying to estimate the probability
density (PD) of cancers within the breast using
the sm library with the routine
sm.density
Of course a practical PD must be limited by the curve of the breast
outline.
I don't have a clue after perusing
2000 Jun 20
1
density estimation in two dimensions
Hello,
I am a newbie to R and the subject of density estimation in two
dimensions or more.
I would like to have some advice concerning a comparison between the R
packages
for density estimation in bivariate or higher order problems; I mean
explicitly
the packages:
1) ash
2) KernSmooth
3) locfit
4) sm.
My specific problem now is having a set of numerical pairs (x_i, y_i),
arising from
a
2001 Apr 30
1
Some loglog density plot
Dear all,
A looong time ago, Witold Eryk Wolski asked here why there wasn't a
log="xy" parameter to the hist() function
<URL:http://www.R-project.org/nocvs/mail/r-help/2001/0267.html>, and
Prof. Ripley responded that a loglog histogram does not make much sense,
and that one should use a better density estimate if one seeks to plot
log density.
I understand the point and I
2003 Jun 17
1
hist density...
Hi!
Do not understand following behavior.
> summary(test$dif)
Min. 1st Qu. Median Mean 3rd Qu. Max.
0.7389 0.9713 0.9850 0.9818 1.0000 1.0000
length(test$dif)
[1] 85879
tmp <- hist(test$dif,breaks=100,freq=FALSE)
The density on the Y axis in the plot are in the range 0-200.
Thought that the density should be in the range 0-1
(something like
2010 Jun 14
1
script development for Unconditional Density and Probability estimation
Hello,
I'd like to automate this script a bit more and cycle several
parameters(both the species and the metric). For example where AnnualDepth
occurs, I need to process about 12 metrics so instead of writing this
entire script 12 times once for each metric I'd like to be able to
automatically get another metric.
Any suggestion will be greatly appreciated.
Currently running Windows
2008 Sep 29
2
density estimate
Hi,
I have a vector or random variables and I'm estimating the density using
"bkde" function in the KernSmooth package. The out put contains two vectors
(x and y), and the R documentation calls y as the density estimates, but my
y-values are not exact density etstimates (since these are numbers larger
than 1)! what is y here? Is it possible to get the true estimated density at
each
2008 Jan 16
1
Probability weights with density estimation
I am a physician examining an NHANES dataset available at the NCHS
website:
http://www.cdc.gov/nchs/about/major/nhanes/nhanes2005-2006/demo_d.xpt
http://www.cdc.gov/nchs/about/major/nhanes/nhanes2005-2006/hdl_d.xpt
http://www.cdc.gov/nchs/about/major/nhanes/nhanes2005-2006/tchol_d.xpt
Thank you to the R authors and the foreign package authors in
particular. Importing from the SAS export
2009 Aug 19
1
Fw: Hist & kernel density estimates
For the hist estimate
>par(mex=1.3)
>dens<-density(q)
>options(scipen=4)
> ylim<-range(dens$y)
> h<-hist(q,breaks="scott",freq=FALSE,probability=TRUE,
+? right=FALSE,xlim=c(9000,16000),ylim=ylim,main="Histogram of q(scott)")
> lines(dens)
>box()
?
For the kernel estimate>options(scipen=4)
> d <- density(q, bw =
2010 Sep 23
3
help in density estimation
Hi, guys,
I'm using kernel "density" estimation. But how can I return to a density
estimation for a fixed point?
For example,
b<-runif(1000,0,1)
f<-density(b)
How can I get the value of density(b) at b=0.5?
Your help is extremely appreciated. Thanks.
Jay
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2006 Jan 31
1
Density estimation with monotonic constaints
Hi All,
I have a sample x={x1,x2,..,xn} fom a distribution with density f. I
wish to estimate the density. I know a priori that the density is
monotonically decreasing. Is there a way to do this in R?
Thanks
Debayan
2004 Apr 10
2
Density Estimation
Dear Sir/Madam;
Would you please tell me what is the command that allows the estimation of the Kernel Density for some data.
Thanks,
Thami Rachidi
[[alternative HTML version deleted]]
2008 Dec 11
2
how to get the CDF of a density() estimation?
Hi,
I've estimated a simple kernel density of a univariate variable with
density(), but after I would like to find out the CDF at specific
values.
How can I do it?
thanks for your help, with it I am very close to finish my first
little bit more serious work in R,
Viktor
2009 Aug 22
1
kernel density estimates
Dear All,
I have a variable q which is a vector of 1000 simulated positive values; that is I generated 1000 samples from the pareto distribution, from each sample I calculated the value of q ( a certain fn in the sample observations), and thus I was left with 1000 values of q and I don't know the distribution of q.
Hence, I used the given code for kernel density estimation to estimate the
2013 Feb 13
1
Kernel Density estimation at specific points
Dear All,
I was wondering whether someone has created a kernel density evaluator that
estimates the density at given specified points.
The regular density() function evaluates the kernel at equidistant points,
but I am interested in doing such evaluation along a list of values
existing in a pre-specified vector. (Similar to the option at() in the
kdensity command in Stata).
This question has