[R] Newbie: How to produce lm results at sub-level within df

[Peter Rooney]

Hi,

Given a data frame:

df1:  application id (appid), project id (pid), person
months (pm), function points (fp)

How do I produce linear modelling results at the appid
level.  That is, I would like to find the coefficent
and intercept for the formula "pm ~ fp" for each
application.

Thanks