Video (6:02) from Research by Design and Dr. Todd Daniel, described as follows, “When we calculate the mean of a sample, we can then use a one-sample t test to compare that sample mean to another mean, such as a mean from a population, a normative group, or another known value (mean). The “one sample” t test is also called a “single sample” t test. You are comparing the mean from a sample to a single mean. This video will introduce you to concepts that you will need later when you learn about hypothesis testing.”

If you’d like to have any of the files used in the video, you can access them here.

In this video (7:49) “You use a paired samples t test in two research designs. One, you conduct a study with a before-and-after design, in which you measure the same sample at two different times with a treatment in between. Two, you have paired participants, such as a study of twin pairs, matched samples, or even puppy siblings from the same litters (see the extended video below). This test is variously called “repeated measures t test,” “repeated t test,” “paired t test,” or “paired samples t test.” All of them use the “within subjects” design. In this video, you will also learn about how to interpret the output of this test.”