Statistically significant

Describes a mathematical measure of difference between groups. The difference is said to be statistically significant if it is greater than what might be expected to happen by chance alone. Also called significant. [NCI]

Scientists use the term “p” to describe the probability of observing such a large difference purely by chance in groups of like people and this is known as the “p-value.” Mathematical probabilities like p-values range from 0 (no chance) to 1 (absolute certainty). So 0.5 means a 50 per cent chance and 0.05 means a 5 per cent chance. In most sciences, results yielding a p-value of .05 are considered on the borderline of statistical significance. If the p-value is under .01, results are considered statistically significant and if it’s below .005 they are considered highly statistically significant. [From:]