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Plotting polynomial fit
2 messages · Ronnen Levinson, David Winsemius
On Apr 26, 2009, at 8:40 PM, Ronnen Levinson wrote:
Hi. Is there an analog to abline() that can be used to plot a polynomial fit? For example, I can draw the straight-line fit fit <- lm(y ~ x) via abline(coef=fit$coef) but I'm not sure how to draw the polynomial fit fit <- lm(y ~ poly(x,2)) I do see the function curve(), but not how to prepare an expr for curve() based on the coefficients returned by the polynomial fit. Thanks for your help,
Use instead the predict function. Something like: lines(x=seq(min(x), max(x), length=100), y= predict( fit, newdata= ....) #insert properly constructed dataframe David Winsemius, MD Heritage Laboratories West Hartford, CT