more psychiatric fairy stories

G

Gerwyn

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A number of studies sponsored by our friends in psychiatry have quoted r values in their claims re causative factors in Me/cfs

for a start r referrs to correlation not causation if there is a strong correlation r must be greater than 0.8 any thing less than 0.5 is weak the lower the weaker.It is quite possible to get a very small pvalue but a very weak correlation

They also can quote confidence intervals----this is actually difficult to describe think of it as a measure of how confident you are that the result is representative of a population and its relatively safe to generqalise from it.In science this normally means that the scatter of your data must be no more than 5% either side of your mean or average value

If you look at the data published by Heim et al claiming a six fold increase in cfs symptoms in those suffereing from self reported child abuse the r value was0.3

and the confidence intervals varied about 70% on each side of the mean that was somehow skewed If I continued to produce fairy stories I,d probably be sectioned----could I suggest the same treatment here!

Saying that cfs symptoms are 6times more likely to occur in patients with CFS than healthy controlls with such a small r value is a little like saying that the symptoms of depression are 6 times more likely than in people who dont have depression!
 
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I never knew there was so much to learn about fairies. Where is the fairy smilie when you need them.

Thank you for that explanation. I have heard about the, less than 0.5 is weak, but what is a p value?
 
G

Gerwyn

Guest
I never knew there was so much to learn about fairies. Where is the fairy smilie when you need them.

Thank you for that explanation. I have heard about the, less than 0.5 is weak, but what is a p value?
Hi v99 p is a measure of probability of the result being due to chance alone A p value has to be less than .05 to be significant this means that the probability of a result occuring purely by chance is less than 5 in a hundred