The Student’s T-Test Calculator is used to determine whether there is a statistically significant difference between a sample mean and a known or hypothesized population mean. It calculates the t-value and corresponding p-value based on the sample mean, population mean, sample standard deviation, and sample size. By selecting one-tailed or two-tailed options, users can assess whether the sample provides enough evidence to reject the null hypothesis. This test is commonly applied in small sample experiments to evaluate population parameters when the population standard deviation is unknown.