t Tests

The t test is a statistical hypotheses in which the test statistic utilizes the t distribution (otherwise known as Student’s t distribution) to define the test conclusion. This test is used when the sample size is small and the distribution appears normal. The z test is very similar, except that it requires knowledge of the population variance (σ2). Without knowing the true variance, the sample variance is used to approximate the population variance, but the t test must be used. Although the t distribution is generally used with unknown variation, the t test need not be used for larger sample sizes. As the sample size increases, the sample variance converges to the population variance, allowing the use of standard normal distribution for testing. In [Page ...