# Notes on designing an experiment

## Proposed statistical analysis

Write down guidelines for the statistical analysis that
you propose to do once the data are collected. Do this *before*
you collect the data: if you cannot think how to analyse the data
then it is a waste of effort to collect it.
For a simple experiment with two treatments and no blocks, you would
probably write `two-sample t-test'. For three treatments and no
blocks, put `analysis of variance with three treatments and no
blocks'.

Do not wait till you have the data before verifying that you can
do the necessary statistical calculation, either with a calculator
or using appropriate software. Unless you have recently analysed an
experiment of exactly the same type, it is a good idea to invent some
dummy data (or copy some from an old experiment) and check that you
know how to get your software to do the correct analysis.

Of course, you may end up doing a different analysis from the one
you proposed. This can happen if somethng goes wrong during the
experiment, or if further information comes to light.

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R. A. Bailey

Page updated 17/11/01