Refer to Scenario 5.1. Adeeb and his team were hoping to conduct their tests in a grocery store. However, they could not receive permission to do so. In the end, they set up a booth in the student union building and asked passers-by to participate. To be more representative, they tried to divide by age and race to ensure they got enough from both genders and from different ethnicities. For instance, they know that roughly 10 percent of the student population at the school is Hispanic. Since its goal is to get 200 responses, they set a goal to ask 20 Hispanic individuals to take the taste test. This is most likely an example of _______.