Variation: use it or misuse it – replication and its variants
This article is being published in The Journal of Physiology, Experimental Physiology, the British Journal of Pharmacology, Advances in Physiology Education, Microcirculation, and Clinical and Experimental Pharmacology and Physiology.
Gordon Drummond is Senior Statistics Editor for The Journal of Physiology.
Sarah Vowler is Senior Statistician in the Bioinformatics Core at Cancer Research UK's Cambridge Research Institute.
This article is the 9th in a series of articles on best practice in statistical reporting. All the articles can be found at http://jp.physoc.org/cgi/collection/stats_reporting
- • Variation between measurements may be reduced if sampling is not random
- • Fixed factors can reduce variation
- • Replicates are repeated measurements from within an experimental unit
- • Replication means that samples can no longer be considered random
- • Comparisons of replicated values require correction, usually by reducing the effect of sample size
- • Correction requires knowledge of the intra-class correlation