Methodology – Power

Statistics:

Power calculations are used to decide how many patients are needed in a trial. They depend on the clinically significant effect which researchers have to define and the mean and standard deviation of the primary outcome.

A type 1 error happens when the researcher wrongly concludes that an intervention works.

A type 2 error happens when the researchers wrongly conclude that an intervention has no effect.

Power is 1 – the chance of a type 2 error.

Put simply, it means the chance of detecting a difference between the groups if one truly existed.