Eight people w/ eight controls?

["Bradshaw, Keith" <Keith.Bradshaw@NNC.CO.UK>]

>The thing that caught my attention most was the size, or lack of, in the

>sample. Eight people w/ eight controls? It's been a long time since my stat

>courses, but I seem to recall needing a minimum of 30 before the data are

>significant.



I think what you recall is you need a minimum of 30 data points to get a

good estimate of the population standard deviation.  But if we believe the

statisticians, it's quite in order to find if two samples (of any n>1 each)

are drawn from the same or different populations at a given level of

confidence.  For approximately normally-distributed results you do this with

the "F-test" coupled with the "t-test".  I'm not saying that this is what

was done in this case, I'm just saying it's possible.  These are in stats

text-books (no doubt there are also more sophisticated tests).



Happy Christmas Radsafers:)



Personal views only



Regards



Keith Bradshaw



Keith Bradshaw

keith.bradshaw@nnc.co.uk

New NNC web site: http://www.nnc.co.uk







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