[R] Plotting power function to practice data

[Peter Ehlers]

Sounds like you might want to use nls() to fit the data
and then use either curve() or predict() to do the
plotting.

  -Peter Ehlers

Dror D Lev wrote:
> Hi,
> 
> I tried to be comprehensive but Jim's comment is indeed in place.
> 
> I have data of a practice experiment where people practice a certain motor
> task and time-to-completion was recorded.
> Appropriately, the time measure declines as practice goes on. And, again
> appropriately, the relation seems to be non-linear. It looks like y=1/x but
> much less steep.
> I understand that the general case of such functions is called
> power-function.
> 
> So what I'm looking for is something like abline() with a power-function fit
> (rather then a linear one).
> 
> Jim is also correct writing that I would like to have separate fits for 'c'
> and 'nc'.
> Of course this can be achieved using subset() but, as Dennis wrote, some
> graphic functions include an option to graph the data by groups.
> 
> Thanks again for any tip or reference.
> 
> dror
> 
> -------------
> 
> On Tue, Dec 29, 2009 at 10:56 PM, jim holtman <jholtman at gmail.com> wrote:
> 
>> It would help if you were more explicit on what you were trying to look
>> at.  I assume that you want two curves ('c' and'nc') on one graphs and you
>> can do that with the basic plot routines, or you can use the 'lattice'
>> package, but without knowing what you are looking for, it is hard to tell.
>>
>> On Tue, Dec 29, 2009 at 3:33 PM, Dror D Lev <dror.teach at gmail.com> wrote:
>>
>>> Hello,
>>>
>>> I have practice data of motor action in the format:
>>>
>>> S  | Cond. | Time
>>> ----+---------+--------
>>> 01 |  c      |  1.23
>>> 01 |  nc    |  0.89
>>> 02 |  c      |  2.15
>>> 02 |  nc    |  1.80
>>> .....
>>>
>>> I want to look at the learning curves graphically.
>>>
>>> I will appreciate pointers to relevant functions / packages.
>>>
>>> Thanks in advance,
>>> dror
>>>
>>>        [[alternative HTML version deleted]]
>>>
>>> ______________________________________________
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>>> PLEASE do read the posting guide
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>>> and provide commented, minimal, self-contained, reproducible code.
>>>
>>
>>
>> --
>> Jim Holtman
>> Cincinnati, OH
>> +1 513 646 9390
>>
>> What is the problem that you are trying to solve?
>>
> 
> 	[[alternative HTML version deleted]]
> 
> ______________________________________________
> R-help at r-project.org mailing list
> https://stat.ethz.ch/mailman/listinfo/r-help
> PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
> and provide commented, minimal, self-contained, reproducible code.
> 
> 

-- 
Peter Ehlers
University of Calgary
403.202.3921