A t-test is a statistical method used to determine if there is a significant difference between the means of two groups. It is commonly employed in hypothesis testing to assess whether the observed differences in sample data reflect true differences in the population. The t-test is particularly useful when dealing with small sample sizes and when the population standard deviation is unknown. There are different types of t-tests, including one-sample, independent two-sample, and paired sample t-tests, each serving specific research scenarios. Understanding t-tests is essential for data analysis in various fields, including psychology, medicine, and social sciences.