## t-Statistic and Degrees of Freedom Calculator

The test statistic for a Student t-test hypothesis test is called a t-statistic. The t-statistic is used to measure how extreme an estimate is. The formula used to calculate t-statistic is the following: $$t = \frac{x - \mu}{s / \sqrt{n}}$$ Where $$x$$ is the mean, $$\mu$$ is the hypothesized mean (in many situations, the hypothesized value is 0), $$s$$ is the standard deviation and $$n$$ is the sample size. Degrees of freedom determines how much a final calculation of a statistic is free to vary. The formula used to calculate it is the following: $$df = n - 1$$ Use the calculator below to solve your t-statistic problems.