[Rd] Use of lm on polynomial models (PR#14014)
Prof Brian Ripley
ripley at stats.ox.ac.uk
Mon Oct 19 11:40:44 CEST 2009
RTFM time: h^3 is not the cube of h in an R formula (for that you need
I(h^3)). See ?formula, for example.
Simpler would be lm(w ~ poly(h, 3, raw=TRUE))
On Sun, 18 Oct 2009, michael_karsh at earthlink.net wrote:
> Full_Name: Michael Aaron Karsh
> Version: 2.8.0.
> OS: Windows XP
> Submission from: (NULL) (18.104.22.168)
> When I try lm(w ~ h^3 + h^2 + h) for example, it only gives
> coefficients for the intercept and for h. It does not give
> coefficients for h^2 or h^3.
So it is behaving correctly.
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-devel