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Line 3: − + − ''Please go to the end of this section to see why I have renamed it from 'confirmed' to 'rebutted'.'' [[User:LongStop|LongStop]] 19:25, 12 October 2008 (EDT)+ − − Line 164:
Line 162: − === Rebuttal of Mr Schlafly's Point 5 === − − Like KennyMac, I've taught statistics to graduate students. The main point he makes is quite correct, that combining experiments will tend to give a more significant result (i.e. a lower P-value) than any single experiment on its own. − − The point that ASchlafly makes (headed '''REPLY''', shortly after KennyMac's example) is slightly misleading. You don't choose which experiments to combine on the basis of their outcomes - you either combine all relevant experiments or none. In this case, Professor Lenski chose to combine all the experiments and present a single analysis of them. That's fine. − − The issue of whether to weight the Z-test according to sample size is not a straightforward issue. Before Whitlock's recent paper, the consensus was that the P-value already depends on sample size so it should not be weighted according to sample size. (Basically, a high degree of significance, i.e. a low P-value, can be achieved by having either a large difference between the treatments or a large experiment or, of course, both.) Whitlock's work, based on computer simulations, is an interesting contribution but cannot be regarded as the last word on the subject because any computer simulation involves assumptions about the structure of the particular experiment simulated. I cannot imagine any editor of a scientific journal rejecting a paper because it used an unweighted Z-test rather than the weighted version (or vice-versa). − − The conclusion, therefore, is that while there is a quantitative difference in the level of significance obtained by weighted and unweighted Z-tests, there is undeniably a significant biological effect. ASchlafly and other contributors should not be concerned that there is anything incorrect about the biological conclusions of Professor Lenski and his students or that there was anything at all underhand about their analysis or presentation of their data. − On a different point, please would CP readers note that there's nothing at all suspicious about a paper being peer-reviewed in only 14 days. Editors of scientific journals ask reviewers beforehand if they are free to edit a paper within a certain period of time. If an academic agrees to review a paper for a prestigious journal such as PNAS within 2 weeks, they will generally ensure they have time during that period to read and comment on the paper thoroughly. [[User:LongStop|LongStop]] 19:25, 12 October 2008 (EDT)
Talk:PNAS Response to Letter (view source)
Revision as of 21:59, October 13, 2008
, 21:59, October 13, 2008Reverted edits by LongStop (Talk); changed back to last version by Aschlafly
Note: earlier posts are archived [[Talk:PNAS_Response_to_Letter/Archive1|here]]. --[[User:BillA|BillA]] 17:05, 20 September 2008 (EDT)
Note: earlier posts are archived [[Talk:PNAS_Response_to_Letter/Archive1|here]]. --[[User:BillA|BillA]] 17:05, 20 September 2008 (EDT)
== Point 5 Rebutted ==
== Point 5 Confirmed ==
I would like to contribute to this discussion because I have taught statistics to graduate biology students for 16 years.
I would like to contribute to this discussion because I have taught statistics to graduate biology students for 16 years. But it doesn't matter who I am - my argument is made on a completely objective basis not on my personal views.
The combination of data from several experiments is a specialist and sometimes difficult area of statistical theory but a simple example shows why Aschafly’s concern about combining the results of three different experiments is not justified and why this aspect of his criticism of Lenski’s recent paper in PNAS is not valid.
The combination of data from several experiments is a specialist and sometimes difficult area of statistical theory but a simple example shows why Aschafly’s concern about combining the results of three different experiments is not justified and why this aspect of his criticism of Lenski’s recent paper in PNAS is not valid.
Maybe the Journal of Nature can be your next letter submission source. ''International Weekly Journal of Science'' -- [[Image:50 star flag.png|14px]] [[User:Jpatt|jp]] 21:17, 22 September 2008 (EDT)
Maybe the Journal of Nature can be your next letter submission source. ''International Weekly Journal of Science'' -- [[Image:50 star flag.png|14px]] [[User:Jpatt|jp]] 21:17, 22 September 2008 (EDT)
== References ==
== References ==
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