The paired t-test is useful for analyzing the same set of items that were
measured under two different conditions, differences in measurements made on
the same subject before and after a treatment, or differences between two
treatments given to the same subject.
For example, a physiologist wants to determine whether a particular fitness
program has an effect on resting heart rate. The heart rates of 15 randomly
selected people were measured prior the program and then measured again one
year later. Therefore, the before and after measurements for each person are a
pair of observations. To see an example, go to
Example of Paired t.
Your data must be continuous values for Y (output). You should have a set
of paired (dependent) observations, such as measurements made on the same item
under different conditions. For more details, go to
Data considerations for Paired t.