>What is wrong with "confidence level"? If we can reject the null
hypothesis
>at the .05 level, we are 95% confident that a real difference exists.
If we are dealing with continuous variables, we are always 100%
confident that a nonzero difference exists, the only issue is the magnitude
of the difference.
Even if it were possible to have a true null hypothesis, you would
have to consider that the 95% probability you refer to as "confidence level"
is a conditional prior probability -- it is the probability that will not
reject the null hypothesis given that it is true. The probability that you
want, the probability that the difference is nonzero given that you have
rejected the null hypothesis, is a distinctly different probability, a
conditional posterior probability. This probability is generally considered
to be indeterminate, given that you need to know the prior probability of
the null hypothesis being true before you can compute it.
+++++++++++++++++++++++++++++++++++++++++
Karl L. Wuensch, Department of Psychology,
East Carolina University, Greenville NC 27858-4353
Voice: 252-328-4102 Fax: 252-328-6283
[EMAIL PROTECTED] <mailto:[EMAIL PROTECTED]>
http://core.ecu.edu/psyc/wuenschk/klw.htm
<http://core.ecu.edu/psyc/wuenschk/klw.htm>
----------
From: [EMAIL PROTECTED] [SMTP:[EMAIL PROTECTED]]
Sent: Friday, September 29, 2000 9:29 AM
To: [EMAIL PROTECTED]
Subject: RE: Clinical vs statistical significance
What is wrong with "confidence level"? If we can reject the null hypothesis
at the .05 level, we are 95% confident that a real difference exists.
Michael B. Quanty, Ph.D.
Psychology Professor
Senior Institutional Researcher
Thomas Nelson Community College
PO Box 9407
Hampton, VA 23670
Phone: 757.825.3500
Fax: 757.825.3807
-----Original Message-----
From: Michael J. Kane [mailto:[EMAIL PROTECTED]]
Sent: Thursday, September 28, 2000 12:33 PM
To: John W. Kulig; DAP Louw (Sielkunde)
Cc: [EMAIL PROTECTED]
Subject: Re: Clinical vs statistical significance
At 09:42 AM 9/28/00 -0400, John W. Kulig wrote:
>(snip)
>Say, isn't it time we revived our discussion about how awkward the term
>"significance" is for p statements? For the "n th" time, wouldn't
>_reliability_ be the better word? If p < .05, we conclude the results of
>the study will repeat if the experiment was replicated. That, in my book,
>is the definition of reliability. This was we can dispense, once and for
>all, with adjectives before the word "significance."
Hi John,
I'd be interested to hear what other Tipsters have to say about this. I
don't
teach stats, but my hunch is that using the word "reliability" would likely
lead students to understand that p = .05 means "if we repeated the study
100 times,
we'd get this result 95 times", when in fact, p = .05 means that *if the
null hypothesis
were true,* then we'd only expect to get this finding 5 times out of a 100.
-Mike
************************************************
Michael J. Kane
Department of Psychology
P.O. Box 26164
University of North Carolina at Greensboro
Greensboro, NC 27402-6164
email: [EMAIL PROTECTED]
phone: 336-256-1022
fax: 336-334-5066
