P -value

P -value probability value; measure of reliability of an observed effect; computed by statistical analyisis of experimental data; term ' P < 0.05' means better than 1:20 (e.g. 0-5%) probability that an observed result occurred by chance, i.e. there is a significant difference between experimental and control data; ' P > 0.05' indicates that, although there may be an observable difference between groups of data, the difference is statistically non-significant