Two-tailed test

A two-tailed test is a statistical method used to determine if there is a significant difference between a sample mean and a population mean, without specifying a direction. In other words, it checks for differences that could be either higher or lower than expected. For example, if you are testing whether a new medication affects blood pressure, a two-tailed test would look for both increases and decreases in blood pressure compared to a standard value. This approach helps ensure that any significant change, in either direction, is identified.