[R] extracting significance test for individual lm() parameters after using by

[Moxley, Jerad]

Sorry I was not clearer, but I was asking an R programming question not a theory question. I will try to clarify. If I did this analysis with a dataset involving  just one subject the summary command on the lm object would give me a significance test on each parameter fit. The question in this cSe, is the cubic parameter significant? When I try to do this for each subject separately in a larger dataset using the by command, I get the parameter estimate but can't find a significance test. I apologize again for my poor explanation originally, 

> On Jan 24, 2015, at 10:04 PM, Jeff Newmiller <jdnewmil at dcn.davis.CA.us> wrote:
> 
> R-square is often a poor indicator of whether a model is appropriate or not. While it is possible that there exists a package that implements your algorithm (which you might find using the sos package), I would recommend that you get some advice from an expert on how to approach this subject, and this list is not a good place for studying statistics theory (read the Posting Guide). You might try stats.stackexchange. com. 
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> Sent from my phone. Please excuse my brevity.
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