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Statistics doesn’t need to be sexy

BMJ 2011; 342 doi: https://doi.org/10.1136/bmj.d651 (Published 02 February 2011) Cite this as: BMJ 2011;342:d651

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Statistical inference: potent if not sexy?

Price is right in concluding that statistical understanding cannot
rely on sexy presentation alone. Sure, this may be feasible for the
description of data. However, the issue is whether inferential statistics
can be so-treated, since this aspect of the discipline provides the
decisions about the worth or not of experimental interventions.

Inferential statistics retains an aura of opaqueness for many
students. In part, this rests on the predominant model based on normal
distributions and - more specifically - sampling distributions. This has a
number of consequences which are not always easily appreciated.

One concerns the fact that computed probababilities may approach -
but never attain - a value of zero. Such an issue raises many questions
regarding how far the model can be violated. The suggestions often seem
rough and ready - and cannot aid the students' basic understanding.

Another concern is that the outcome of significance testing reflects
the size of the sample: the larger the sample, the more likely a
significant effect is to be demonstrated. It is not often clear to many
students that a feable effect can be significant if we just use a large
enough sample.

Such important issues are never likely to be sexy, no matter how
potent they may be! Nor are they likely to vanish: alternatives to
significance testing never seem to make much headway.

Competing interests: No competing interests

07 February 2011
Tony A. Reinhardt-Rutland
Reader in Psychology
University of Ulster