Differences
Analysis of paired data is based on the difference between the two measurements made from each individual.
Examples
The question of interest for paired data can often be expressed in terms of hypotheses about the mean difference.
Analysis of paired data
By taking differences, much of the variability between the individuals is eliminated. This provides considerably more information to help assess the null and alternative hypotheses.
The benefits of pairing will be explained more fully in a later page.
Garage repair estimates