Comparing meansmean scores between two different groups/samples is the independent sample t-test. However, if the data comecomes from within-subjects (or repeated measures design) isit's called the paired samples (Warner, 2013). In other words, the paired-samples t-test comparecompares the means of two variables for a single group. For example, in a study on impact of IPadan iPad ASL storybook on Deafdeaf first graders’ reading comprehension skills. All the first graders at a Deafdeaf school are to take the pre-test at the beginning of the study, provide IPaduse an iPad ASL storybook on a fixed schedule, and take the post-test. Therefore, each subject has two measures, before and after.