Question

Professor Proust, a memory researcher, designs an experiment to test the hypothesis that reading

picture books designed for children significantly enhances college students' memories of childhood.
She asks participants to wri
te about significant childhood memories, and to circle any events they
remember from a list of common memories (such as getting lost in a store or breaking a leg, etc.).
Use the following terms to describe how Professor Proust should choose the p
articipants and
experimental/control groups for her study:
• Population
• Random sample
• Random assignment

Answer 1

The correct answer is: random assigment of a predefined number of individuals from the population of interest to either the control or the experimental/treatment groups.

This system of assignment is used to ensure that each member of the population of interest has exactly the same probability of being chosen for either of the groups, in order to avoid sampling biases that could subsequently contaminate the results of the experiment.

• Random selection is different in the sense that is simply ensures a respresentative sample from a population, but it does not rule out sampling biases when creating the experimental and control groups.
• Using the whole population is intractable, as the population of interest comprises all the people who fulfill the requirement of being college students. Therefore, it is not possible to invite all college students to the experiment and some type of sampling is required.