lines() not properly displaying quadratic fit

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I'm simply trying to display the fit I've generated using lm(), but the lines function is giving me a weird result in which there are multiple lines coming out of one point.

Here is my code:

library(ISLR)
data(Wage)
lm.mod<-lm(wage~poly(age, 4), data=Wage)
Wage$lm.fit<-predict(lm.mod, Wage)

plot(Wage$age, Wage$wage)
lines(Wage$age, Wage$lm.fit, col="blue")

I've tried resetting my plot with dev.off(), but I've had no luck. I'm using rStudio. FWIW, the line shows up perfectly fine if I make the regression linear only, but as soon as I make it quadratic or higher (using I(age^2) or poly()), I get a weird graph. Also, the points() function works fine with poly().

Thanks for the help.

asked 33 secs ago

user3476573

1