[R] How to create density ellipses with R
j|ox @end|ng |rom mcm@@ter@c@
Fri Jan 14 19:53:55 CET 2022
On 2022-01-14 1:17 p.m., Paul Bernal wrote:
> Dear John and R community friends,
> To be a little bit more specific, what I need to accomplish is the
> creation of a confidence interval ellipse over a scatterplot at
> different percentiles. The confidence interval ellipses should be drawn
> over the scatterplot.
I'm not sure what you mean. Confidence ellipses are for regression
coefficients and so are on the scale of the coefficients; data
(concentration) ellipses are for and on the scale of the explanatory
variables. As it turns out, for a linear model, the former is the
rescaled 90 degree rotation of the latter.
Because the scatterplot of the (two) variables has the variables on the
axes, a data ellipse but not a confidence ellipse makes sense (i.e., is
in the proper units). Data ellipses are drawn by car::dataEllipse() and
(as explained by Martin Maechler) cluster::ellipsoidPoints(); confidence
ellipses are drawn by car::confidenceEllipse() and the various methods
I hope this helps,
> Any other guidance will be greatly appreciated.
> El vie, 14 ene 2022 a las 11:27, John Fox (<jfox using mcmaster.ca
> <mailto:jfox using mcmaster.ca>>) escribió:
> Dear Paul,
> As I understand it, the ellipse package is meant for drawing confidence
> ellipses, not density (i.e., data) ellipses. You should be able to use
> ellipse::ellipse() to draw a bivariate-normal density ellipse (assuming
> that's what you want), but you'll have to do some computation first.
> You might find the dataEllipse() function in the car package more
> convenient (again assuming that you want bivariate-normal density
> I hope this helps,
> John Fox, Professor Emeritus
> McMaster University
> Hamilton, Ontario, Canada
> web: https://socialsciences.mcmaster.ca/jfox/
> On 2022-01-14 10:12 a.m., Paul Bernal wrote:
> > Dear R friends,
> > Happy new year to you all. Not quite sure if this is the proper
> place to
> > ask about this, so I apologize if it is not, and if it isn´t,
> maybe you can
> > point me to the right place.
> > I would like to know if there is any R package that allows me to
> > density ellipses. Searching through the net, I came across a
> package called
> > ellipse, but I'm not sure if this is the one I should use.
> > Any help and/or guidance will be greatly appreciated.
> > Best regards,
> > Paul
> > [[alternative HTML version deleted]]
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