Good day for all,
I'm a beginner aRgonaut, thus I'm having a problem to plot a quadratic model
of regression in a plot.
First I wrote:
plot(Y~X)
and then I tried:
abline(lm(Y~X+I(X^2))
but abline only uses the first two of three regression coefficients, thus
I tried:
line(lm(Y~X+I(X^2))
but
I hardly use base graphics so I'm no help there. You can do this
easily with ggplot2 though:
library(ggplot2)
X - rnorm(100)
Y - rnorm(100) - X^2
qplot(x=X, y=Y, geom=c(point, smooth), method=lm, formula = y ~
poly(x, 2))
Note that X is not x and Y is not y in the sense that formula = Y ~
see ?curve
e.g.
qftn - function(x) 1 + 2*x - .1*x^2
curve(qftn, 0, 10)
hth,
Kingsford
On Mon, Oct 5, 2009 at 9:42 AM, Juliano van Melis jvme...@gmail.com wrote:
Good day for all,
I'm a beginner aRgonaut, thus I'm having a problem to plot a quadratic model
of regression in a plot.
First I
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