[R] How to plot error bars

[Uwe Ligges]

On Wed, 8 Nov 2000, Mike Beddo wrote:

> I'm a newcomer to R. I can't seem to find any documentation how to add
> error bars to points in scatter plots. I guess I could plot the points,
> then compute and plot line segments in the X and/or Y directions to
> represent the errors?

You are right.
You can plot the points, fit a model (e.g. using lm()), and plot the
"error bars" or residuals. Have a look at e.g. str(lm(...)), maybe you
don't need to calculate fitted values / residuals manually.
In some cases there are already existing plot methods ...

Finally: To plot line segments you might want to use segments().

Regards,
Uwe Ligges

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