[R] Plotting a Quadratic...

From: Ryan Harrigan <iluvsa_at_ucla.edu>
Date: Wed, 31 Dec 1969 16:16:39 -0800


I have an equation describing the best-fit model for a set of points (just 2 axes) that is in the form:

y=b+mx+px^2

Where b is the intercept, m is the slope describing a linear term, and p is a slope of the quadratic term.

I would like to plot this equation on a curve (I know the equation is y=(.1766x^2)+(.171x)+.101) on the original scatterplot. Any easy way to plot this equation and preferably with a prediction interval around the line?

I have tried the lines() and predict() commands, using the linear model to plot, but get very whacky results. abline works great but does not include the quadratic term.

Any help you could provide would be much appreciated,

Ryan Harigan

--
Ryan Harrigan, Ph.D.
Center for Tropical Research
Institute of the Environment
La Kretz Hall, Suite 300
Box 951496
Los Angeles, CA 90095-1496
203-804-9505
iluvsa_at_ucla.edu

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Received on Thu 22 May 2008 - 18:06:21 GMT

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