The level of confidence of a test of hypothesis is denoted by a percentage value, usually denoted by α, which is also known as the significance level or alpha level. The confidence level represents the probability that the null hypothesis will be rejected when it is actually true. For example, if the significance level is set at 5%, then there is a 5% chance of rejecting the null hypothesis when it is actually true. Generally, the confidence level is set at 95% or 99%, which means that there is a 5% or 1% chance, respectively, of rejecting the null hypothesis when it is actually true.