**Introduction:**

**Power or Statistical Power of a test is defined as the probability of not committing a Type II error i.e. the probability that the test will reject the null hypothesis when it is false.**

**The probability of Type II error is denoted by β. Hence the probability of not committing a Type II error is 1 – β. Hence the power of a test is denoted by 1 –β.**

**Use:**

**Statistical Power is used to determine the sample size that is minimum required in order to make one more likely to locate the effect of a given size.**

**Statistical power is also used to compare between different procedures of statistical test.**