d Samples T-TestPair sample t-test and dependent sample t-test are used to see if the mean differences in the two observation tests will remain at zero. The pair test is measured twice to see the pairs of observations. This method is used when they are observing case-control studies and repeated measures designs. As, an example is a company that wants to see the effectiveness of how company training is working. The observer can measure a sample of employees before the training and then another sample study after completing the training. They can find by the analyses if they are genuinely effective or no different. (Aron, Coups, & Aron, 2013).