On Tue, Jul 24, 2012 at 11:53 AM, Douglas N Greve <greve@nmr.mgh.harvard.edu> wrote:

Hi Jurgen, I don't think it is too unusual to do this kind of thing, ie,
a paired test where pairing is based on gender, age, and education, but
you know your data and field better than I do. It is not the case that
one is more conservative than another (they are the same) assuming that
the underlying assumptions are met. The underlying assumptions are more
stringent for the paired than for the unpaired.
doug

On 07/24/2012 06:22 AM, Jürgen Hänggi wrote:
> Dear statistic experts
>
> We have done statistics between two independent groups using an independent
> t-test. One group consistent of 13 male patients and the other group
> consistent of 13 male control subjects who were matched to the patients with
> respect to age and education (in years).
>
> The reviewer proposed that it might be more appropriate to use a paired
> t-test.
> However, we can imaging a design where such an approach is adequate e.g.
> monozygotic twins reared in shared environments who are discordant for a
> particular trait.
>
> In our opinion, the matching of only age and education is not sufficient in
> order to apply a paired t-test.
> In addition, the paired t-test is more anti-conservative than the
> independent t-test and therefore advantages our hypothesis and this might be
> identified as a statistical "trick" by other reviewers.
>
> Any comment about whether or not the suggested paired t-test is appropriate
> in our study is highly appreciated.
>
> Thanks in advance
> Regards
> Jürgen Hänggi
>
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> Division Neuropsychology
> Institute of Psychology
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--
Douglas N. Greve, Ph.D.
MGH-NMR Center
greve@nmr.mgh.harvard.edu
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