Power of study can be increased by
Power of a Test:
– Is probability of rejecting a Null hypothesis when a predetermined clinically significant difference is indeed
present
– Measures the ability to demonstrate an association, when one really exists
– Power of a statistical test: 1 – b ( 1 – probability of Type II error)
– Power of a statistical test is complimentary to b (probability of Type II error)
– Power of a statistical test is a numeric representation of: Sensitivity
– Power of a statistical test can be increased by:
1. Increasing the no. of subjects in a trial (sample size)
2. Reducing b (probability of Type II error)
3. Increasing sensitivity
– Power of a statistical test is also used for calculation of sample size for a study
Increasing a error
Increasing b error
Decreasing a error
Decreasing b error