This dataset example introduces readers to the Wilcoxon signed-rank test. This technique allows researchers to test whether there is a difference between two related groups of measurements. Hence, it is commonly used to study any change in the subjects from one time point to another, or to compare the effects of different treatments/conditions. This example uses a subset of data from the Health Insurance Marketplace Public Use Files released by the Centers for Medicare & Medicaid Services (CMS). It examines any change in the average rate of plans offered by insurance issuers between the years 2014 and 2016 (before and after most provisions of the Affordable Care Act took effect). Results from an analysis like this could reveal changes in health care systems and inform public health policies.In this example, readers are introduced to the basic theory and assumptions underlying this technique, the type of questions this technique can be used to answer, and how to produce and report results. The sample dataset has been cleaned and organized to make this example easier to follow. Interested readers should read the full documentation for the dataset before using it for research (https://www.cms.gov/cciio/resources/data-resources/marketplace-puf.html).