Paul,
I think you need 8760*(number of subjects followed for a year) assuming the
124 heart attacks were from more than one subject. Then you could do a test
as to whether or not marijuana in a given hour is associated with heart
attack in that hour.
The hours for a fixed subject are not independent so you shouldn't lump them
together in a contingency table. One possible approach would be to do a
logistic regression with the person/hours being the observations, so that
there are 8760*(number of subjects followed for a year) observations. A
positive response is a heart attack and the predictors are MJ use that hour
and N-1dummy variables for the subjects. Then you want to look at the sign
and p-value of the MJ coefficient.
Hope this helps.
Ellen Hertz
"Paul Jones" <[EMAIL PROTECTED]> wrote in message
[EMAIL PROTECTED]">news:[EMAIL PROTECTED]...
> There was some research recently linking heart attacks with
> Marijuana smoking.
>
> I'm trying to work out the correlation and, most
> importantly, its statistical significance.
>
> In essence the problem comes down to:
>
> Of 8760 hours in a year, 124 had heart attacks in them, 141
> had MJ smokes in them and 9 had both.
>
> What statistical tests apply?
> Most importantly, what is the statistical significance of
> the correlation between smoking MJ in any hour and having a
> heart attack in that same hour?
> What is the probablity that the null hypothesis (that
> smoking marijuana and having a heart attack are unrelated)
> can be rejected?
> How reliable are the results from a dataset of this size?
>
> I'm not very literate in maths and stats - please help me
> out someone. I'm interested in this research from the
> perspective of medicinal marijuana.
>
> Thanks and take care,
> Paul
> All About MS - the latest MS News and Views
> http://www.mult-sclerosis.org/
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