[R] power?
Simon Blomberg
s.blomberg1 at uq.edu.au
Wed Oct 7 08:35:58 CEST 2009
The short answer is Yes. If you reject the null hypothesis based on that
p-value, then by definition you had enough power to do that. This is
because there is a precise inverse relationship between the p-value and
the "observed" power, once you fix the effect size and the sample size.
In other words, your post-hoc power analysis would be a simple
re-statement of the p-value. There is no extra information that can be
gained from such an analysis. See:
The American Statistician, February 2001, Vol. 55, No. 1, pp 19-24
Don't bother with your power analysis, unless you are planning a new
experiment.
Simon.
On Tue, 2009-10-06 at 13:49 -0700, SNN wrote:
> Hi,
>
> I have used multiple linear regression on a data set and one if the
> regressor was significant with a p-value =0.01
>
> I need to calculate the power for a multiple linear regression. i.e. do I
> have enough power to believe the above p-value?
>
>
>
>
--
Simon Blomberg, BSc (Hons), PhD, MAppStat.
Lecturer and Consultant Statistician
School of Biological Sciences
The University of Queensland
St. Lucia Queensland 4072
Australia
Room 320 Goddard Building (8)
T: +61 7 3365 2506
http://www.uq.edu.au/~uqsblomb
email: S.Blomberg1_at_uq.edu.au
Policies:
1. I will NOT analyse your data for you.
2. Your deadline is your problem.
Statistics is the grammar of science - Karl Pearson
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