similar to: [S] confidence ellipsoid for model parameters

Dear all, Has anyone written functions to compute (and ideally project / plot onto a plane) confidence ellipsoids for q linear model parameters, q > 2 ? Greetings and best wishes, Renaud -- Dr Renaud Lancelot, v?t?rinaire CIRAD, D?partement Elevage et M?decine V?t?rinaire (CIRAD-Emvt) Programme Productions Animales http://www.cirad.fr/presentation/programmes/prod-ani.shtml ISRA-LNERV

I have a 3xN matrix of parameters obtained from N regressions where the 3 parameters are jointly statistically significant. I would like to reproduce a 3D confidence ellipsoid projecting 2D ellipses onto the XY plane as in Figure 5.2 in this

Full_Name: Volker Franz Version: Version 1.6.2 (2003-01-10) OS: Debian Submission from: (NULL) (192.124.28.104) Hi there, it seems to me that data.ellipse of package "car" (Version 1.0-1) produces confidence interval's which are too big. To see this, do: library(car) plot(c(-2,2),c(-2,2),pch=0) data.ellipse(rnorm(10000),rnorm(10000),levels=0.68,plot.points=F) abline(v=+1)

+ Hello, The parametric equations of an ellipsoid can be written in terms of spherical coordinates. The three spherical coordinates are converted to Cartesian coordinates by X=a cos (α) sin(θ) Y=b sin(α) sin(θ) Z=c cos(θ) for α and θ The parameter α varies from 0 to 2 π and θ varies from 0 to π . Here ( X o , Y o ,Z o ) is the center of the ellipsoid, and θ is the angle

Hi, I'm using the R library(car) to draw confidence/prediction ellipses in a scatterplot. >From what i understood the ellipse() function return an ellipse based parameters: shape, center, radius . If i read dataEllipse() function i can see how these parameters are calculated for a confidence ellipse. ibrary(car) a=c(12,12,4,5,63,63,23) b=c(13,15,7,10,73,83,43) v <-

I am curious if there is code developed to plot confidence regions in 3D. The scatterplot3d function generates the plot I want, but would like an 3D equivalent to the data.ellipse function. Any help in this direction would be appreciated, be it theoretical, graphical, or otherwise. Melanie Edwards Senior Statistician Exponent 15375 SE 30th PL, Suite 250 Bellevue, WA 98007 Tel: (425) 519-8714

Hi all, Can anyone please guide me how to draw a Concentration ellipsoid for a bivariate system with a bivariate normal dist. having a VCV matrix : Sigma <- matrix(c(1,2,2,5), 2, 2) I would like to draw in using GGPLOT. Your help will be highly appreciated. Thanks, -- View this message in context: http://www.nabble.com/Concentration-ellipsoid-tp25315705p25315705.html Sent from the R help

Hello everyone I really need some help here. I made a confidence ellipse using the function ellipse from the package ellipse: ellipse(SD, centre=colMeans(pcsref),t=sqrt((p * (n-1)/(n-p))*qf(0.99, p,n-p)) Now, I want to write a function whom return TRUE or FALSE if a given observation is in the confidence ellipse. But I have no clue how to do it Can anyone help me? Best regards Jessica

Hello, in a three dimensional coordinate system, I'd like to find all my experimental data points that fall within an ellipsoid around a fixed coordinate. The fixed point is defined by (x.coord.point, y.coord.point, z.coord.point). The coordinates of the ellipsoid are given by the three vectors x,y,z. In a previous version of my code, I simply used a box instead of an ellipsoid to sort

Dear All, I would be very appreciative of your help with the following 1). I am running multivariate multiple regression through the manova() function (kindly suggested by Professor Venables) and getting two different answers for test=c("Wilks","Roy","Pillai") and tests=c("Wilks","Roy",'"Pillai") as shown below. In the

Dear list, I'm trying to visualise some ellipsoidal shapes in 3D. Their position, axes, and angular orientation can be arbitrary. I saw an ellipse3d function in rgl; however it is heavily oriented towards the statistical concept of ellipse of confidence, whilst I am just concerned with the geometrical object. Below is my current implementation. It is quite slow when creating many shapes, so

Hi: Does Ellipse and dataellipse function in R produce the same ellipse? I wanted to see how the radius for the Ellipse function in R calculated. Also what is the var-covariance matrix, if any, assumed for the dataellipse function? Heres an example of the code where I am generating Multivariate normal data and creating ellipse using the 2 functions: library(car) library(mvtnorm) mu =

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,

Hi!, I made a plot with two variables representing the first two axis of a principle component analysis. My question is: How can I superimpose on such plot an ellipse that represent the 95% interval of confidence of scores? Best regards, Paula -- Lic. Paula Gonzalez Divisi??n Antropolog??a Museo de La Plata. Facultad de Ciencias Naturales y Museo. UNLP. Paseo del Bosque s/n?? - B1900FWA - La

List, Would someone be so kind as to point me to a function that will calculate simultaneous confidence intervals of regression coefficients based upon their distribution as (under the assumption of normal errors, with \mathbf{X} as the design matrix): $\hat{\mathbf{\beta}} \sim N(\mathbf{\beta}, \sigma^2(\mathbf{X}^T\mathbf{X})^{-1})$. 'confint' calculates individual coefficients so

Hey, all I am going to plot several 3-dimensional ellipsoids in R. For example, A is such a ellipsoid with mean u=[1 1 1]', covariance matrix C=[1 0 .5;0 1 .6;.5 .6 1]; So how can I plot such object in 3D space? Is there some function to achieve this? Thanks. Fred

Dear All, The Minimum Volume Ellipsoid estimator ("cov.mve") was part of S+ but I cannot find it in R. Where can I find it? Why was it excluded? Cheers, Patrik Sweden

I am interested in making a random sample from a uniform distribution of points over the surface of the earth, using the WGS84 ellipsoid as a model for the earth. I know how to do this for a sphere, but would like to do better. I can supply random numbers, want latitude longitude pairs out. Can anyone point me at a solution? Thanks very much. -- Russell Senior ``I have nine fingers;

After a lot of effort I developed the following function to compute the bounding ellipse (also known a as minimum volume enclosing ellipsoid) for any set of points. This script is limited to two dimensions, but I believe with minor modification the algorithm should work for 3 or more dimensions. It seems to work well (although I don't know if can be optimized to run faster) and

The mvee() function is intended to be released under the BSD license. Copyright (c) 2009, Nima Moshtagh Copyright (c) 2011, Andy Lyons All rights reserved. http://www.opensource.org/licenses/bsd-license.php Redistribution and use in source and binary forms, with or without modification, are permitted provided that the following conditions are met: Redistributions of source code must