Replicate and randomize, or lie.
Biological populations are naturally variable. Investigators need to replicate observations to estimate their characteristics. They must also randomize selection to estimate those characteristics without bias and with known confidence. Both replication and randomization are necessary.
Rothamsted Research, Harpenden, AL5 2JQ, UK.
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D015982:Bias; D035843:Biomedical Research / Q000379:methods*; D006801:Humans; D019370:Observation / Q000379:methods*; D011897:Random Allocation