A T-test is a statistical method used to determine if there is a significant difference between the means of two groups. It helps researchers understand whether the differences observed in sample data are likely to reflect true differences in the larger population. T-tests are commonly used in various fields, including psychology, medicine, and social sciences. There are different types of T-tests, such as the independent T-test, which compares two separate groups, and the paired T-test, which compares two related groups. The results of a T-test are often expressed as a p-value, indicating the probability that the observed differences occurred by chance.