pleaseee help (marketing)

Match the examples on the left to the concept they are related to on the right. You are running a five part study over the course of 5 weeks. You started with 200 respondents but ended only with 40 participants who completed all the 5 parts of the test. You are measuring the strength of a group of respondents. For their selection in the experiment you take them to a gym and ask them to perform rigorous activity for an hour. Now, the respondents who qualify your pretest criteria are taken to the gym immediately and asked to lift heavy weights (so that you can measure their strength)