What symbol indicates the significance level in statistical testing?

In statistical testing, the symbol that indicates the significance level is α (alpha). This represents the threshold for determining whether to reject the null hypothesis. The significance level is the probability of making a Type I error, which occurs when one incorrectly rejects a true null hypothesis. Common values for α are 0.05, 0.01, and 0.10, which correspond to a 5%, 1%, and 10% risk of concluding that a difference exists when there is none.

The other symbols represent different concepts in statistics. For instance, β (beta) relates to the Type II error rate, which measures the probability of failing to reject a false null hypothesis. The symbol σ (sigma) denotes the standard deviation of a population, which is a measure of the amount of variation or dispersion in a set of values. Lastly, µ (mu) represents the mean of a population, which is a measure of central tendency. These symbols play important roles in statistics but are not used to denote the significance level in hypothesis testing.