Matheus,
Yes, your test was flawed. Remember the assumptions of ANOVA - normal
residuals, equality of variances. Two replicates are too few to
adequately test the assumption of equality of variance among treatments
(and we know nothing of the residual test). If you are unable to test
the assumptions of the anova due to small sample size, the anova should
not be done. A power of 1 or 0.99 usually means that there was some
trivial and self-evident result of your ANOVA, but it can also mean that
your data were also insufficient to test power.
I have been teaching biostatistics to grad students for several years
now. In this class, for every topic the students must find a research
paper published in a top journal on the same topic and analyze the
analysis. We have found that a very significant portion (> 25%) of the
papers analyzed have statistics have flaws that range from minor to
major. ALL of these are peer reviewed.
Cheers,
Jim
Matheus Carvalho wrote on 09-Jul-09 20:01:
Changing a little the topic, I have a question about the statement of Edwin. He
wrote:
"If the statistics are grossly inappropriate (for example running an
ANOVA with 12 treatments, but only 1 or two replicates per treatment),
adequate peer review was clearly not in place."
Well, I published a paper in which I used 2 way ANOVA with a total of 18 groups
and 2 replicates per groups. It was peer reviewed, and one of the reviewers
complained about my statistics, asking for measurements of power, perhaps with
the expectation that that particular test would have no enough power to draw
any conclusions. I used a software to measure the power of the test (G*power
3), and found that power was the maximum possible (1.00) for the effects due to
factors 1 and 2, and 0.99 for the interaction effect.Was my test flawed? It was
peer reviewed!
Best,
Matheus C. Carvalho
Postdoctoral Fellow
Research Center for Environmental Changes
Academia Sinica
Taipei, Taiwan
--- Em qui, 9/7/09, Edwin Cruz-Rivera <edwin.cruz-riv...@jsums.edu> escreveu:
De: Edwin Cruz-Rivera <edwin.cruz-riv...@jsums.edu>
Assunto: Re: [ECOLOG-L] "real" versus "fake" peer-reviewed journals
Para: ECOLOG-L@LISTSERV.UMD.EDU
Data: Quinta-feira, 9 de Julho de 2009, 10:37
I believe one of the original questions was how to discern reputable
journals from those that publish dubious or biased results...or do not
accomplish proper peer review. I can point to a couple of red flags that
can be noticed without too much effort and I have observed:
1) If the articles in the journal come mostly from the same institution in
which the editor in chief is located, chances are the buddy system has
overwhelmed objectivity...especially if the editor is a co-author in most.
2) If orthographic and syntax errors are widespread, probably the review
process was not thorough.
3) If the statistics are grossly inappropriate (for example running an
ANOVA with 12 treatments, but only 1 or two replicates per treatment),
adequate peer review was clearly not in place.
Now these may look like extreme cases, but I have seen too many examples
similar to the above to wonder how widespread these cases are. I have
even received requests to review papers for certain journals in which I
have been asked to be more lenient than if I was reviewing for a major
journal. This poses a particular dilemma: Is all science not supposed to
be measured by the same standards of quality control regardless of whether
the journal is institutional, regional, national or international?
I would like to think it should be...
Edwin
------------------------------------------------------------------
Dr. Edwin Cruz-Rivera
Assist. Prof./Director, Marine Sciences Program
Department of Biology
Jackson State University
JSU Box18540
Jackson, MS 39217
Tel: (601) 979-3461
Fax: (601) 979-5853
Email: edwin.cruz-riv...@jsums.edu
"It is not the same to hear the devil as it is to see him coming your way"
(Puerto Rican proverb)
____________________________________________________________________________________
Veja quais são os assuntos do momento no Yahoo! +Buscados
http://br.maisbuscados.yahoo.com
