View Full Version : Re: Stats Power. Report Confidence Limits - p values

01-26-2005, 02:34 AM
Would anyone like to comment on clinical significance?

For example, my dentist can completely cure temporomandibular joint
dysfunction (TMJ) in 80% of patients by applying a plastic splint to
the teeth. Scientifically, this is not statistically significant. It
does not even approach statistical significance. So statistically we
would accept the null hypothesis that there is no difference in the
treatment of TMJ by using this device or not because the level of
confidence is only 80%.

Statistically, my dentist is a failure, but clinically, a world-beater!


At 9:58 AM -0500 1/26/05, Dr. Chris Kirtley wrote:
>This brings up an interesting issue. I spoke to a statistician last year who
>told me that the only reason Fischer came up with these tables, and indeed the
>whole concept of significance testing, was because there were no computers
>available at that time. He considered T-tests, ANOVAs etc. to be stopgap
>methods that could to be used to get an approximate estimate until better
>computing power came along (as he expected it would).
>If Fischer were to be alive today, he would likely be appalled that we are
>still using his extremely simplified methods. Apparently any decent real
>statistician worth his salt these days performs a simulation in order to
>compute the likelihood of error. I was never able to find out how
>this is done,
>but perhaps someone else on the list can enlighten us? It really is
>time all of
>us in biomechanics moved into the modern age!
>Bryan Kirking wrote:
>> To comment and question some of Dr. Allison's insight:
>> >>My understanding of the arbitrary "line in the sand" of 0.05 was
>> >>originally due to the choice of the original tables (pre computer)
>Dr. Chris Kirtley MD PhD
>Associate Professor
>Dept. of Biomedical Engineering
>Catholic University of America
>Washington DC 20064
>Alternative email: kirtleymd@yahoo.com
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Bruce Etnyre, Ph.D., P.T.
Kinesiology Department
Professor and Chair
Rice University
6100 Main MS 545
Houston, Texas 77005
Phone: (713)348-5936 or 8816

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