Thanks for replying, David. I'll try to frame the problem
better.
First, I shall explain my motivations.
There has recently been some research that implied that
smoking MJ increased risk of heart attack in the hour
following the heart attack. I haven't got the full text of
the article - I've just seen the abstract, the press
releases and resultant press coverage. There is a lot of
dodgy research research and I want to know how statistically
valid this research is.
As you can imagine this topic is of great interest to people
who use medicinal marijuana for multiple sclerosis as it has
considerable benefit for neurogenic bladder problems,
neuropathic pain and muscle spasms. The headline that MJ may
increase heart attack risk in the hour following smoking it
is extremely pertinent to people with MS. This explains my
motives. This is not homework - I have MS.
So the research says that of a large number of people who
had heart attacks at a centre, 124 people had used MJ in the
year preceding the HA. Of these 9 reported that they had
used MJ in the hour preceding the HA. All MJ users were
questioned on the frequency with which they used MJ. The
relative risk was reported as 4.8 - I used this to
back-calculate that the average number of MJ usages per year
rounded 141 -> (9/n)/(115/(8760-n)) = 4.8
I see an immediate mistake in what I wrote before - I have
used the average Med MJ smokes but the total heart attacks.
Restating the problem:
Event A is smoking MJ.
Event B is having HA.
Let's assume that both events can only happen once per hour
and that each person only had one HA.
Of 1,086,240 hours, A happened 17,484 times, B happened 124
times and both A and B happened 9 times.
What I want to know is what is the correlation between these
two event?
Most importantly, how statistically significant is the
result?
Can any reasonable conclusions be drawn from these data -
esp, in view of the small dataset size?
I would appreciate being corrected.
Take care,
Paul
All About MS - the latest MS News and Views
http://www.mult-sclerosis.org/
"David C. Ullrich" wrote:
>
> 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.
>
> >Thanks and take care,
> >Paul
> >All About MS - the latest MS News and Views
> >http://www.mult-sclerosis.org/
>
> David C. Ullrich
> *********************
> "Sometimes you can have access violations all the
> time and the program still works." (Michael Caracena,
> comp.lang.pascal.delphi.misc 5/1/01)
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