It appears the answer to your goal after a discursive exploration of
"interpolation", which was really extrapolation, is that you need to
look at the predict methods for linear (and other sorts as well) models.
?predict
?predict.lm
> y <- c(16,45,77,101,125)
> x <- c(0,5,10,15,20)
>
> lmmod <- lm(y ~ x)
> plot(x,y, ylim = c(0,125), xlim =c(-4,22)) #defaults would not
allow estimates from plot
> lines(x=seq(-4,22, by=.5),
y=predict(lm(y ~ x), newdata = data.frame(x = seq(-4,22, by=.
5) ) ) )
--
David Winsemius
On Jan 15, 2009, at 11:31 AM, e-letter wrote:
snipped preceding excursion
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