Answer:
The answer is random selection.
Explanation:
Random selection refers to a process in which there is a representative sample that is used for a specific study. Random means that people that are involved in the sample are chosen by chance. Thus, there are the same probabilities for each person to be chosen.
A random selection is important to scientists because the scientist's purpose is to generalize his or her findings related to the whole population. However, the purpose is not testing the whole population. Thus, the scientist chooses a specific group of people and selects people at random.