[R] Comparing Time Series

nathan3073 nathan.3073 at gmail.com
Mon Mar 31 14:37:31 CEST 2008


It is a reaction time experiment. My program will display 25 circles,
arranged in a 5x5 square. The program will light one circle at a time, which
the subject should click ASAP. The time interval between two lighting is
1.5s. If the subject fails to click in approriate time, the data will be
considered missing.

The one I want to explore is the relationship between intellegence and the
ability to recognize visual stimuli regularity. I arrange the experiment so
there will be 4 repeated pattern. At last, after all pattern have been
displayed, my program will light the circle randomly.

I want to check the time series plots, in order to clarify my hypothesis
that the 'smart' and the 'average' deal with stimuli in a different way. For
example, because of 'smart' people is known to be able to recognize
regularity faster, we may expect their plot to decline quite rapidly. But,
because of their automation, we may also expect that they will find some
difficulties to adapt when the pattern has changed. The adaptation
difficulty may be represented (hopefully) by an increasing reaction time.

I think to check every subject's plot, and determine their ARIMA(p,d,q)
model. Then, if they all follow same ARIMA model, obviously my hypothesis is
wrong, and I may conclude that there are no differences in the way subject
deal with stimuli. But, if let's say 20 subject follow ARIMA(1,0,1) and the
others follow ARIMA(0,0,2) I can say that there are differences in the
subject's cognitive ability for dealing with stimuli. For now, I set aside
what the differences is and its psychological explanation.

The problem is, it will be very frustating to have 200 subjects and
determine approriate ARIMA model for each plot. So, there're only 2 ways
left. One, I reduce the number of subjects to manageable quantity, let's say
30 subjects. Or two, I know method(s) that make me possible to analyze
multiple time series plot, and say whether they follow same or different
model.

Thank you,
regards,
Nathanael

PS: please forgive grammatical error


Prof Brian Ripley wrote:
> 
> Surely you need the insight before choosing a package?
> 
> What is the problem you are trying to solve?  There are many different 
> aspects of time series which could be of interest, and we have no idea 
> which are relevant to your problem.
> 
> On Sun, 30 Mar 2008, nathan3073 wrote:
> 
>>
>> Dear All,
>> I need to compare hundreds (about 200-300) of time series. Would anyone
>> tell
>> me how to do this in R? If R has no package for doing this, can I get
>> some
>> insight what method I should use?
>>
>> best regards,
>> Nathanael Gratias
>> --
>> View this message in context:
>> http://www.nabble.com/Comparing-Time-Series-tp16392632p16392632.html
>> Sent from the R help mailing list archive at Nabble.com.
>>
>> ______________________________________________
>> 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.
>>
> 
> -- 
> Brian D. Ripley,                  ripley at stats.ox.ac.uk
> Professor of Applied Statistics,  http://www.stats.ox.ac.uk/~ripley/
> University of Oxford,             Tel:  +44 1865 272861 (self)
> 1 South Parks Road,                     +44 1865 272866 (PA)
> Oxford OX1 3TG, UK                Fax:  +44 1865 272595
> 
> ______________________________________________
> 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.
> 
> 

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