ABSTRACT
The t-test is used to see if the difference between two means is statistically significant. There are multiple kinds of t-tests. This chapter focuses on the t-test for independent groups. The dependent groups t-test, by contrast, compares means drawn from related groups, like having the same group take a test on two different occasions and comparing the mean score. The chapter covers the t-test for dependent groups. The t-test yields a p-value, which indicates the probability that chance or random sampling errors created the difference between the means. As with many statistical tests, most researchers consider a difference to be statistically significant when p <.05. When it does, the null hypothesis is rejected. Like many things in statistics, the t-test for independent groups goes by multiple names. This can be confusing. The t-test for independent groups is also called: independent t-test for two samples, independent-samples t-test, and Student's t-test.
