[R] Quartile regression question
phgrosjean at sciviews.org
Fri Jun 13 21:55:37 CEST 2008
Look at package quantreg.
Ranney, Steven wrote:
> I have data that looks like
> I can regress log weight on log length simply enough, but how would I model the third quartile of log weights? In other words, rather than finding a 2nd quartile (or 50th percentile) regression line,
> e.g., mod=lm(logweight~loglength)
> can R find a 75th percentile line? Further, since my data is lake>1, is there a way to run 3rd quartile regressions on each lake? I would imagine that regressing each population would require some call of the subset function, but I cannot figure out how to call it.
> Thanks in advance,
> Steven H. Ranney
> Graduate Research Assistant (Ph.D)
> USGS Montana Cooperative Fishery Research Unit
> Montana State University
> PO Box 173460
> Bozeman, MT 59717-3460
> phone: (406) 994-6643
> fax: (406) 994-7479
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