A military psychologist is interested in studying the effects of relaxation training on a visual perception test. He gets a group of soldiers and a group of pilots. He exposes the pilots to a relaxation training and then administers the visual perception test to both groups. He finds that the group exposed to relaxation training did much better and concludes this was due to the relaxation technique.

1.Identify a potential extraneous variable. (1 point)

2.Describe how the extraneous variable might be confounding the results. Your response should be 1–2 sentences long. (2 points)

Write a short response to each of the following in your own words. (5 questions, 1–2 points each, 8 points total)

3.Define and give an example of systematic variability. Your response should be 1–2 sentences long. (2 points)

4.Define and give an example of random variability. Your response should be 1–2 sentences long. (2 points)

5.Describe two differences between a between-subjects design and a within-subjects design. Your response should be 2–4 sentences long. (2 points)

6.Define power. Your response should be 1–2 sentences long. (1 point)

7.Give an example of what a researcher might do to increase power in a study. Your response should be 1–2 sentences long. (1 point)

Fill in the blank. (8 blanks, 1 point each, 8 points total) 

1. 8.One strength of ____________________ is that it eliminates random error associated with identified extraneous participant variables.

1. 9.When a researcher doesn’t want to leave it to chance that important variables will be equally distributed across conditions, she would employ ____________________ to ensure this happens.

1. 10.____________________ is a fairly easy way to put participants into conditions, though it is not an approach that should be used with small samples.

1. 11.The pre-posttest design is an example of a ____________________ approach to research design. 

1. 12.A professor who takes care to make sure her research assistants (those who are in charge of administering the experimental conditions) are of different racial backgrounds, ages, gender, and religions is most likely trying to eliminate ____________________ in her study. 

1. 13.When all possible orders of the different levels of an independent variable are used in a repeated-measures design, it is known as ____________________. This differs from ____________________, in which only some of the possible orders are used. Each of these approaches is meant to control for the influence of ____________________.