Final answer:
A t-test is a significance test that assesses the means of two independent groups. The Aspin-Welch t-test is used when the population standard deviations are unknown and possibly unequal. In a hypothesis test for matched or paired samples, the test is performed on the population mean of the differences.
Step-by-step explanation:
A t-test is a significance test that assesses the means of two independent groups.
When performing a t-test, there are assumptions that need to be met, such as having a simple random sample and data that is approximately normally distributed.
The Aspin-Welch t-test is used when the population standard deviations are unknown and possibly unequal. In a hypothesis test for matched or paired samples, the test is performed on the population mean of the differences.