What does “statistical significance” mean?
In statistics, a result is statistically significant if it is unlikely to have occurred by chance. For example, if a group of patients treated with a particular drug result have a statistically significant increase in survival time compared to a group treated with a placebo, it means that the increased survival is due to the drug treatment and not some other random effect. In some studies there may be an observed effect on survival but not a statistically significant one. This means that it is not possible to conclusively say that the observed survival effects are due to the treatment or whether it is natural variation within the population studied.
