Displaying 20 results from an estimated 9000 matches similar to: "kernel density estimation and classification"
2005 Jul 01
1
p-values for classification
Dear All,
I'm classifying some data with various methods (binary classification). I'm interpreting the results via a confusion matrix from which I calculate the sensitifity and the fdr. The classifiers are trained on 575 data points and my test set has 50 data points.
I'd like to calculate p-values for obtaining <=fdr and >=sensitifity for each classifier. I was thinking about
2020 Oct 09
2
2 D density plot interpretation and manipulating the data
> My understanding is that this represents bivariate normal
> approximation of the data which uses the kernel density function to
> test for inclusion within a level set. (please correct me)
You can fit a bivariate normal distribution by computing five parameters.
Two means, two standard deviations (or two variances) and one
correlation (or covariance) coefficient.
The bivariate normal
2020 Oct 09
0
2 D density plot interpretation and manipulating the data
Hi Abby,
thank you for getting back to me and for this useful information.
I'm trying to detect the outliers in my distribution based of mean and
variance. Can I see that from the plot I provided? Would outliers be
outside of ellipses? If so how do I extract those from my data frame,
based on which parameter?
So I am trying to connect outliers based on what the plot is showing:
s <-
2020 Oct 09
2
2 D density plot interpretation and manipulating the data
I recommend that you consult with a local statistical expert. Much of what
you say (outliers?!?) seems to make little sense, and your statistical
knowledge seems minimal. Perhaps more to the point, none of your questions
can be properly answered without subject matter context, which this list is
not designed to provide. That's why I believe you need local expertise.
Bert Gunter
"The
2020 Oct 09
0
2 D density plot interpretation and manipulating the data
Hi Bert,
Another confrontational response from you...
You might have noticed that I use the word "outlier" carefully in this
post and only in relation to the plotted ellipses. I do not know the
underlying algorithm of geom_density_2d() and therefore I am having an
issue of how to interpret the plot. I was hoping someone here knows
that and can help me.
Ana
On Fri, Oct 9, 2020 at
2020 Oct 09
0
2 D density plot interpretation and manipulating the data
My understanding is that this represents bivariate normal
approximation of the data which uses the kernel density function to
test for inclusion within a level set. (please correct me)
In order to exclude the outlier to these ellipses/contours is it
advisable to do something like this:
SNP$density <- get_density(SNP$mean, SNP$var)
> summary(SNP$density)
Min. 1st Qu. Median Mean 3rd
2020 Oct 09
3
2 D density plot interpretation and manipulating the data
You could assign a density value to each point.
Maybe you've done that already...?
Then trim the lowest n (number of) data points
Or trim the lowest p (proportion of) data points.
e.g.
Remove the data points with the 20 lowest density values.
Or remove the data points with the lowest 5% of density values.
I'll let you decide whether that is a good idea or a bad idea.
And if it's a
2020 Oct 09
0
2 D density plot interpretation and manipulating the data
Hi Abby,
Thanks for getting back to me, yes I believe I did that by doing this:
SNP$density <- get_density(SNP$mean, SNP$var)
> summary(SNP$density)
Min. 1st Qu. Median Mean 3rd Qu. Max.
0 383 696 738 1170 1789
where get_density() is function from here:
https://slowkow.com/notes/ggplot2-color-by-density/
and keep only entries with density > 400
2004 Oct 12
1
bandwidths for bivariate density estimation
Hi,
I am using the KernSmooth package to estimate nonparametrically bivariate
density functions. However, it seems that the bandwidths (one for each
co-ordinate direction) have to be selected manually. This does not apply
for the univariate case, for which dpik (included in KernSmooth) uses
up-to-date plug-in rules.
Does anyone know about a package, or function, which estimates bandwidths
2020 Oct 08
2
2 D density plot interpretation and manipulating the data
Hello,
I have a data frame like this:
> head(SNP)
mean var sd
FQC.10090295 0.0327 0.002678 0.0517
FQC.10119363 0.0220 0.000978 0.0313
FQC.10132112 0.0275 0.002088 0.0457
FQC.10201128 0.0169 0.000289 0.0170
FQC.10208432 0.0443 0.004081 0.0639
FQC.10218466 0.0116 0.000131 0.0115
...
and I am creating plot like this:
s <- ggplot(SNP, mapping = aes(x = mean, y = var))
2004 Mar 17
3
Persp plotting of kernel density estimate.
Dear All,
I am trying to visualize the surface of a bivariate kernel density
estimate.
I have a vector of bivariate observations(x,y), and a function which
computes the kernel density estimate z corresponding to each
observation.
I cannot generate the (x,y) data in the ascending order needed by
persp(x,y,z).
I was wondering whether there is an R version of the S function interp.
Would anybody
2006 Apr 23
3
bivariate weighted kernel density estimator
Is there code for bivariate kernel density estimation?
For bivariate kernels there is
kde2d in MASS
kde2d.g in GRASS
KernSur in GenKern
(list probably incomplete)
but none of them seems to accept a weight parameter
(like density does since R 2.2.0)
--
Erich Neuwirth, University of Vienna
Faculty of Computer Science
Computer Supported Didactics Working Group
Visit our SunSITE at
2010 Sep 07
1
boundary correction - univariate kernel density estimation
Hey,
Does anyone know of a package in R that provides univariate kernel
density estimation with boundary correction ?
or how to easily extend an existing bivariate kernel density estimation
function (e.g. lambdahat in the spatialkernel package) with boundary
corrections to allow univariate density estimation?
Thanks a lot,
Steve B.
--
View this message in context:
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
2012 Jul 03
1
saving contour() plot info
{ I think this message got rejected at the 1st attempt - trying again}
R 2.15.1 , windows XP
I have a very non-stationary bivariate time-series - say {xt,yt} t=1 ... lots.
I want to do a bivariate density contour-plot of the whole series and then step
through the series 1 second at a time plotting that second's {x,y} subset on top of the contour
plot and losing the previous
2010 Jan 01
2
How to calculate density function of Bivariate binomial distribution
Am trying to do some study on bivariate binomial distribution. Anyone knows
if there is package in R that I can use to calculate the density function of
bivariate binomial distribution and to generate random samples of it.
Thanks,
--
View this message in context: http://n4.nabble.com/How-to-calculate-density-function-of-Bivariate-binomial-distribution-tp992002p992002.html
Sent from the R help
2012 Mar 23
1
Nonparametric bivariate distribution estimation and sampling
Dear all,
I have a bivariate dataset from a preliminary study. I want to do two things: (1) estimate the probability density of this bivariate distribution using some nonparametric method (kernel, spline etc); (2) sample a big dataset from this bivariate distribution for a simulation study.
Is there any good method or package I can use in R for my work? I don?t want parametric models like
2011 Oct 19
1
Estimating bivariate normal density with constrains
Dear R-Users
I would like to estimate a constrained bivariate normal density, the
constraint being that the means are of equal magnitude but of opposite
signs. So I need to estimate four parameters:
mu (meanvector (mu,-mu))
sigma_1 and sigma_2 (two sd deviations)
rho (correlation coefficient)
I have looked at several packages, including Gaussian mixture models in
Mclust, but I am not sure
2004 Nov 17
1
how to estimate conditional density
Hi, there.
Suppose I have a bivariate data set y1 and y2. Can anybody tell me how to
estimate the conditional density of f(y1|y2) and vice versa? Thanks.
Yulei
$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$
Yulei He
1586 Murfin Ave. Apt 37
Ann Arbor, MI 48105-3135
yuleih at umich.edu
734-647-0305(H)
734-763-0421(O)
734-763-0427(O)
734-764-8263(fax)
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2019 Mar 29
2
Test failure due to file path
Hi all,
The following tests fail because my username (csabaraduly) contains "bar" :
********************
FAIL: LLVM :: tools/llvm-objcopy/ELF/regex.test (47099 of 50832)
******************** TEST 'LLVM :: tools/llvm-objcopy/ELF/regex.test'
FAILED ********************
Script:
--
: 'RUN: at line 1';
/home/csabaraduly/wk/LLVM-git/__build_release_99/bin/yaml2obj