In article <9galk6$fjr$[EMAIL PROTECTED]>,
"Mr Unreliable" <[EMAIL PROTECTED]> wrote:
> David C. Ullrich wrote in message <[EMAIL PROTECTED]>...
>
> >On Thu, 14 Jun 2001 15:22:25 +0100, Paul Jones
> ><[EMAIL PROTECTED]> wrote:
> >
> >>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?
> >
> >None. What you've said here makes no sense - what does
> >it mean for an _hour_ to have MJ smoke?
> >
> >If you're actually reporting on actual research it
> >would be interesting to know what the actual researchers
> >actually said - if there's actual "research" out there
> >that talks about the number of hours in a year containing
> >smoke that will be remarkable.
> >
> >If otoh this is a homework question you should quote
> >the question more accurately. (If the homework question
> >_really_ reads _exactly_ the way you put it then you
> >should complain to whoever assigned it that it makes
> >no sense.)
> >
> >>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?
> >
> >Now this sounds more like you're talking about one
> >person. This is an actual person who actually had
> >124 heart attacks in one year? I doubt it.
> >
> >>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.
> >
> >Fascinating topic. If this is not actually homework you
> >need to explain the question much more accurately.
>
> The data presented may refer to a much-reported study. (See, for example,
> http://www.eurekalert.org/releases/bidm-bsf022800.html
> )
>
>
> To quote from there:
>
> "The findings are the latest to emerge from a multicenter study of 3,882
> patients who survived heart attacks. In this report, 124 people reported
> using marijuana regularly. Of these, 37 people reported using marijuana
> within 24 hours of their heart attacks, and nine smoked marijuana within an
> hour of their heart attacks."
So the people who died from heart attacks weren't even considered in the
study. Perhaps of all the people who had heart attacks, recent mj use
was statistically correlated with saving their lives. That would be
consistent with what you just described. So the methodology sounds
bogus.
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