Do read ?poly: you have orthogonal polynomials. On Tue, 3 Feb 2004, Timur Elzhov wrote:
> Dear R experts, > > Excuse me if my question will be stupid... > I'd like to fit data with x^2 polynomial: > > d <- read.table(file = "Oleg.dat", head = TRUE) > d > X T > 3720.00 4.113 > 3715.00 4.123 > 3710.00 4.132 > ... > > out <- lm(T ~ poly(X, 4), data = d) You asked for 4 and got 2? Really? > out > Call: > lm(formula = T ~ poly(X, 2), data = d) > > Coefficients: > (Intercept) poly(X, 2)1 poly(X, 2)2 > 9.803 -108.075 51.007 > > So, d$T best fitted with function > 9.803 -108.075 * X + 51.007 * X^2, > yes? No! -- Brian D. Ripley, [EMAIL PROTECTED] 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 ______________________________________________ [EMAIL PROTECTED] mailing list https://www.stat.math.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide! http://www.R-project.org/posting-guide.html