[R] Violation of sample independence in Pearson's product-moment correlation

[Bert Gunter]

The reviewers are right.

But this is not an R question at all. Post on a statistics list like
stats.stackexchange.com.

Much better yet, consult a local statistician, as it is abundantly
clear that you have insufficient statistical background to properly
analyze your data.

Cheers,
Bert

On Fri, Jun 1, 2012 at 10:15 AM, Justin Montemarano <jmontema at kent.edu> wrote:
> Hi all:
>
> There was a concern raised by reviewers of a manuscript of mine over the
> proper execution of a Pearson's correlation. In brief, this was undertaken
> in order to determine the relationship between the extent of wheel running
> (y axis) and ethanol intake (x axis) across three, separate 10 day periods
> in 7 animals.
>
> In the paper, the correlational plots for each 10 day-period had 70 data
> points: One point for each day and each animal across 10 days of
> experimentation. The reviewers, however, appropriately pointed out that
> this is a violation of the assumption of sample independence for Pearson's
> test, and I should have had only 7 points, which would reflect the means of
> my two variables for each individual animal across 10 days. Is this
> appropriate or is there a means of accounting for repeated sampling with a
> correlation test?
>
> -
> Justin Montemarano
> Graduate Student
> Kent State University - Biological Sciences
>
> http://www.montegraphia.com
>
>        [[alternative HTML version deleted]]
>
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-- 

Bert Gunter
Genentech Nonclinical Biostatistics

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