[R] statistical advice

2008-09-03 Thread Allison Brager
Hello,

I am a researcher in sleep and circadian rhythms who is having much trouble
deciding on proper statistical analyses. Before I state my question, I
provide a brief synopsis of the looming problem; I am interested in activity
bout distributions across a 24 hr day. In addition to looking at the number
of activity bouts across the day, I am also interested in the duration of
each activity bout. My current method of analyzing numbers and durations of
activity bouts involves; 1) documenting the number of activity bouts for
each condition  (alcohol or water drinker) and then, using repeated measures
ANOVA to account for three days of activity recording 2) displaying the
number of each bout duration (expressed in 15 minute bins) in a frequency
histogram, that again, documents differences in bout number between
conditions. My concern lies in the size of the frequency bins for the bout
durations. My advisor suggested 15  min bins, my co-advisor suggests 60 min,
I think 10 min (from *Quantitative analysis of the age-related fragmentation
of hamster 24-h activity rhythms* by Plamen D. Penev, Phyllis C. Zee, and
Fred W. Turek) which leads me to my question: IS THERE A MORE CONTINUOUS WAY
OF ANALYZING ACTIVITY DURATION DIFFERENCES THAT DOES NOT INVOLVE "COUNTING"?

If you would like more insight on my experiment in order to have a more
accurate understanding of the problem, please do not hesitate to contact me.

Sincerely,
Allison Brager

-- 
Graduate Student
Department of Biological Sciences
Kent State University

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Re: [R] statistical advice

2008-09-03 Thread Greg Snow
I have had luck using the circular and the CircStats packages to look at sleep 
related data.  I have fit mixtures of vonmeises distributions to time of 
occurance responses (have not looked at duration with time of occurance).  
There are also tools for doing regression models with circular responses (time 
of day) and either linear or circular predictors.  If you want to use a 
circular predictor to predict a non-circular response then there are tools for 
doing periodic splines which work in that case.

Hope this helps,  If you give more detail of what you want to accomplish 
(either in the mailing list, or offline), then we/I can give more detail.

--
Gregory (Greg) L. Snow Ph.D.
Statistical Data Center
Intermountain Healthcare
[EMAIL PROTECTED]
(801) 408-8111



> -Original Message-
> From: [EMAIL PROTECTED]
> [mailto:[EMAIL PROTECTED] On Behalf Of Allison Brager
> Sent: Wednesday, September 03, 2008 10:44 AM
> To: r-help@r-project.org
> Subject: [R] statistical advice
>
> Hello,
>
> I am a researcher in sleep and circadian rhythms who is
> having much trouble deciding on proper statistical analyses.
> Before I state my question, I provide a brief synopsis of the
> looming problem; I am interested in activity bout
> distributions across a 24 hr day. In addition to looking at
> the number of activity bouts across the day, I am also
> interested in the duration of each activity bout. My current
> method of analyzing numbers and durations of activity bouts
> involves; 1) documenting the number of activity bouts for
> each condition  (alcohol or water drinker) and then, using
> repeated measures ANOVA to account for three days of activity
> recording 2) displaying the number of each bout duration
> (expressed in 15 minute bins) in a frequency histogram, that
> again, documents differences in bout number between
> conditions. My concern lies in the size of the frequency bins
> for the bout durations. My advisor suggested 15  min bins, my
> co-advisor suggests 60 min, I think 10 min (from
> *Quantitative analysis of the age-related fragmentation of
> hamster 24-h activity rhythms* by Plamen D. Penev, Phyllis C.
> Zee, and Fred W. Turek) which leads me to my question: IS
> THERE A MORE CONTINUOUS WAY OF ANALYZING ACTIVITY DURATION
> DIFFERENCES THAT DOES NOT INVOLVE "COUNTING"?
>
> If you would like more insight on my experiment in order to
> have a more accurate understanding of the problem, please do
> not hesitate to contact me.
>
> Sincerely,
> Allison Brager
>
> --
> Graduate Student
> Department of Biological Sciences
> Kent State University
>
> [[alternative HTML version deleted]]
>
> __
> R-help@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.
>

__
R-help@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.