In a message dated 4/7/2010 9:17:37 A.M. Mountain Daylight Time,
[log in to unmask] writes:
In general, any test should involve at least 12 normalized colonies in
each
group...
... the two most important metrics are bee
population (frame strength, which would include mortality), and weight
gain.
I agree with the 12 colonies as a goal - my stats say that 6 is probably
the minimum number for most things- but if you have several variables, you
may have to settle for less than 12 per subset due to time/cost factors.
However, as you know, we've seen pesticide studies where subsamples of the
same colony were considered to be replications (which they clearly are not).
As per metrics, its a lot of work, but if there's any chance of a
reproductive effect, you need to follow amount of brood and its survival.
Finally, I've given up trying to normalize colonies - they just revert
back to strong, medium, weak, regardless of what you do - I've even gone as far
as using sister queens hand inseminated to the same drones, with no real
improvement. Lay out your colony acceptance criteria before starting the
trial, then rank all of the colonies, apportion them in equal strengths,
etc. to each treatment. In other words, if you have 3 treatments plus a
control, and if you have 48 colonies, when ranked from strongest to weakest,
you'd take the top four and randomly assign one to each treat/control, then
the next four, etc.
Jerry
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