Thanks Prof Ripley.
For anybody else wondering about this, see:
http://stackoverflow.com/questions/26728289/extracting-orthogonal-polynomial-coefficients-from-rs-poly-function
=
The polynomials are defined recursively using the alpha and norm2
coefficients of the poly
This method of finding yhat as x %*% b works when I use raw polynomials:
x-1:8
y- 1+ 1*x + .5*x^2
fit-lm(y~poly(x,2,raw=T))
b-coef(fit)
xfit-seq(min(x),max(x),length=20)
yfit-b[1] + poly(xfit,2,raw=T) %*% b[-1]
plot(x,y)
lines(xfit,yfit)
But it doesn't work when I use orthogonal polynomials:
On 14/01/2015 14:20, Stanislav Aggerwal wrote:
This method of finding yhat as x %*% b works when I use raw polynomials:
x-1:8
y- 1+ 1*x + .5*x^2
fit-lm(y~poly(x,2,raw=T))
b-coef(fit)
xfit-seq(min(x),max(x),length=20)
yfit-b[1] + poly(xfit,2,raw=T) %*% b[-1]
plot(x,y)
lines(xfit,yfit)
But it
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