[R] MASS library rob.cov ellipse
Prof Brian Ripley
ripley at stats.ox.ac.uk
Tue Jul 3 07:32:51 CEST 2007
On Mon, 2 Jul 2007, Jenifer Larson-Hall wrote:
> I used to get a really useful graph when I ran the following command
> using the MASS library:
> Besides the regular output, a graph appeared that had the classical
> correlation and the robust correlation, and two ellipses, one
> surrounding the data that would be used in the classical correlation and
> the other surrounding the data in the robust correlation.
But all the data are 'used in the classical correlation'. Maybe you mean
a tolerance ellipse for the implied bivariate normal distribution?
> I've searched through the MASS library but don't see a separate command
> that could produce this graph. Does anyone know whether one exists, or
> did the graph just disappear in the newer version of R?
It was never in the MASS *package*. cov.rob() is mainly intended for
multidimensional problems, not 2D ones. It is possible you were using
methods from package 'robustbase', such as covPlot?
The author of cov.rob.
> Thanks for any help,
> Dr. Jenifer Larson-Hall
> Assistant Professor of Linguistics
> University of North Texas
Brian D. Ripley, ripley at stats.ox.ac.uk
Professor of Applied Statistics, http://www.stats.ox.ac.uk/~ripley/
University of Oxford, Tel: +44 1865 272861 (self)
1 South Parks Road, +44 1865 272866 (PA)
Oxford OX1 3TG, UK Fax: +44 1865 272595
More information about the R-help