R help - Oct 2013 - over dispersion plot

I want to show over dispersion in my data by plotting the variance against
the mean for 8 groups.  I used the following code to plot by type
(parasite).

scatterplot(variance~mean | parasite, reg.line=lm, smooth=FALSE,
spread=FALSE, boxplots=FALSE, span=0.5, by.groups=TRUE, data=Disp2)

I now want to add a hypothetical regression line that would show what a 1:1
ratio would look on the same plot.

I also want to label specific points by their sample name, or by a specific
color.

help please?

-- 
Sagan C. Friant, MSc
Environment & Resources Ph.D Program
Nelson Institute of Environmental Studies
University of Wisconsin - Madison

	[[alternative HTML version deleted]]

At 19:15 01/10/2013, Sagan Friant wrote:
>I want to show over dispersion in my data by plotting the variance against
>the mean for 8 groups.  I used the following code to plot by type
>(parasite).
>
>scatterplot(variance~mean | parasite, reg.line=lm, smooth=FALSE,
>spread=FALSE, boxplots=FALSE, span=0.5, by.groups=TRUE, data=Disp2)
If you are going to get meaningful help you need to be open with us 
about what you did. Where did you get the function scatterplot from?

>I now want to add a hypothetical regression line that would show what a 1:1
>ratio would look on the same plot.
It may be that you can do this with abline but in the absence of more 
details about scatterplot it is hard to be sure.
>I also want to label specific points by their sample name, or by a specific
>color.
>
>help please?
>
>--
>Sagan C. Friant, MSc
>Environment & Resources Ph.D Program
>Nelson Institute of Environmental Studies
>University of Wisconsin - Madison
>
>         [[alternative HTML version deleted]]
Michael Dewey
info at aghmed.fsnet.co.uk
http://www.aghmed.fsnet.co.uk/home.html