What you want is
lm(T ~ X + I(X^2), data = d)
Regards, Sundar
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)
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$T best fitted with function 9.803 -108.075 * X + 51.007 * X^2, yes?
T1 <- 9.803 -108.075 * d$X + 51.007 * d$X^2 T1 705453240 703557595 701664500 699773956 ...
So, T1 obviosly gets non-sensible values.. :( Why? Thanks a lot!
-- WBR, Timur.
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