Arches. Photo by Daniel Chia
Jul
05
2011

statistically significant

A result is called ‘statistically significant’ if it is unlikely to have occurred by chance. Statistical significance acts as a cut-off point; if a drug causes a statistically significant improvement in symptoms, it has passed the cut-off point, and is considered to be a good treatment. Most studies set a significance level of 0.05, meaning that their findings must only a 5% probability of occurring by chance to be considered significant.