Displaying 20 results from an estimated 300 matches similar to: "2 D density plot interpretation and manipulating the data"
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
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 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
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
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
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
2009 Feb 08
0
Initial values of the parameters of a garch-Model
Dear all,
I'm using R 2.8.1 under Windows Vista on a dual core 2,4 GhZ with 4 GB
of RAM.
I'm trying to reproduce a result out of "Analysis of Financial Time
Series" by Ruey Tsay.
In R I'm using the fGarch library.
After fitting a ar(3)-garch(1,1)-model
> model<-garchFit(~arma(3,0)+garch(1,1), analyse)
I'm saving the results via
> result<-model
2005 Jan 07
0
Missing functionality in Blowfish for crypt(3)
The blowfish crypt(3) mechanism supports the use of a "cost value" for password encryption. The cost value is encoded into the encrypted password that is stored in master.passwd. On OpenBSD, this cost value can be set in login.conf. FreeBSD does not currently support the cost value. The cost value is the base-2 logarithm of the number of rounds of encryption to use so
2006 Oct 09
2
Add ellipse to plot
Is there a way to plot elliptical shapes? symbols() only provides circles...
Thanks!
Kamila
2011 Nov 01
2
drawing ellipses in R
Hello,
I have been following the thread dated Monday, October 9, 2006 when Kamila Naxerova asked a question about plotting elliptical shapes. Can you explain the equations for X and Y. I believe they used the parametric form of x and y (x=r cos(theta), y=r sin(theta). I don't know what r is here ? Can you explain 1)the origin of these equations and 2) what is r?
Sincerely,
Mary A. Marion
2010 Mar 28
3
Ellipse that Contains 95% of the Observed Data
I can take the results of a simulation with one random variable and generate
an empirical interval that contains 95% of the observations, e.g.,
x <- rnorm(10000)
quantile(x,probs=c(0.025,0.975))
Is there an R function that can take the results from two random variables
and generate an empirical ellipse that contains 95% of the observations,
e.g.,
x <- rnorm(10000)
y <- rnorm(10000)
?
2012 Mar 09
2
rgl: cylinder3d() with elliptical cross-section
For a paper dealing with generalized ellipsoids, I want to illustrate in
3D an ellipsoid that is unbounded
in one dimension, having the shape of an infinite cylinder along, say,
z, but whose cross-section in (x,y)
is an ellipse, say, given by the 2x2 matrix cov(x,y).
I've looked at rgl:::cylinder3d, but don't see any way to make it
accomplish this. Does anyone have
any ideas?
thx,
2006 Feb 28
1
Collinearity in nls problem
Dear R-Help list,
I have a nonlinear least squares problem, which involves a changepoint;
at the beginning, the outcome y is constant, and after a delay, t0, y
follows a biexponential decay. I log-transform the data, to stabilize
the error variance. At time t < t0, my model is
log(y_i)=log(exp(a0)+exp(b0))
at time t >= t0, the model is
log(y_i)=log(exp(a0-a1*(t_i - t0))+exp(b0=b1*(t_i -
2006 Sep 29
2
GLM information matrix
Is there a function that provides the Fisher information matrix for a
generalized linear model? I do not see how to access the off-diagonal
matrix elements of the value returned by glm. (I'm particularly
interested in logistic regression.)
If not, what is a good way to use R to compute Hessians or other partial
derivatives of log likelihoods?
I would appreciate any guidance.
David
2002 May 23
5
logistic regression or discriminant analysis ?
Hello,
Does logistic regression really provide better results than lda or qda ?
(my purpose is not classification but highlighting of discriminant
variables).
If this is true, where could I get an R script performing stepwise logistic
regression ?
Thanks
--
Daniel AMORESE
Lab. M2C "Morphodynamique Continentale et C?ti?re"
UMR CNRS 6143 Caen/Rouen
Centre de G?omorphologie
UCBN
2010 Oct 24
6
Contour Plot on a non Rectangular Grid
Dear All,
I would like to plot a scalar (e.g. a temperature) on a non-rectangular
domain (or even better: I would simply like to be able to draw a contour
plot on an arbitrary 2D domain). I wonder if there is any tool to
achieve that with R. I did some online search in particular on the list
archives, found several queries similar to this one but was not able to
find any conclusive answer.
I
2008 Oct 10
1
how to evaluate a cubic Bezier curve (B-spline?) given the four control points
I'm trying to use R to determine the quality of a cubic Bezier curve
approximation of an elliptical arc. I know the four control points
and I want to compute (x,y) coordinates of many points on the curve.
I can't find anything in either the base distribution or CRAN that
does this; all the spline-related packages seem to be about *fitting*
piecewise Bezier curves to a data set.
2003 Apr 23
1
clustering
Dear R-users,
I have a two - dimensional data set which needs to be clustered into
groups:
I'm searching for groups of points which show a positive
correlation (in a twodimensional plot of the data set), but I do not have
any knowledge about how many groups there might be.
Do you know of a clustering algorithm in R (or
in general) which can use a-priori information about the cluster's
2002 Oct 02
4
T-Distribution
Dear sir,
I would ask if there are in R some code to generate a random sample
from a mvariate student distribution like that one wich generate the
multivariate normal one i mean( rmvnorm(n, mu, sigma)
Second question : if R can plot density 3Dcurve I don't mean de
histogram but de hole density function(normal for example).
I use a windows version of The R software
Thank you in advance
wiyh