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

George Havenith
01-27-2005, 07:38 PM
For stuff like this a great place to read about stats is the following site:

for clinical applications I suggest you look up 'clinical versus
statistical significance'. This also links to some powerpoint presentations
containing a very interesting view on how something can be clinically
relevant even if not significant.

regards, George

At 16:34 26/01/2005, Bruce Etnyre, Ph.D., P.T. wrote:
>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
>To unsubscribe send SIGNOFF BIOMCH-L to LISTSERV@nic.surfnet.nl
>For information and archives: http://isb.ri.ccf.org/biomch-l

Dr. G.Havenith, Reader in Environmental -Physiology and -Ergonomics
Dept. Human Sciences phone +44 (0)1509
Human Thermal Environments Laboratory fax +44 (0)1509 223940
Loughborough University, LE11 3TU, UK E-mail: G.Havenith@lboro.ac.uk
URL: http://www-staff.lboro.ac.uk/~hugh/index.html

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