Week Four Homework Exercise
Answer the following questions, covering material from Ch 8–10 of Methods in Behavioral Research:
- What is a confounding variable and why do researchers try to eliminate confounding variables? Provide two examples of confounding variables.
- What are the advantages and disadvantages of posttest only design and pretest-posttest design?
- What is meant by sensitivity of a dependent variable?
- What are the differences between an independent groups design and a repeated measures design?
- How does an experimenter’s expectations and participant expectations affect outcomes?
- Provide an example of a factorial design. What are the key features of a factorial design? What are the advantages of a factorial design?
- Describe at least four different dependent variables.
- What are some ways researchers can manipulate independent variables?
- What is the difference between main effects and interactions?
- How do moderator variables impact results? Provide an example.
- A researcher is interested in studying the effects of story endings on preference ratings. He randomly assigns participants into two groups: predictable ending or surprise ending. He instructs them to read the story and provide preference ratings. The experimenter’s variation of story endings is a __________ (straightforward or staged) manipulation.
- A researcher was interested in investigating the vocabulary skills of 6th graders in a program for gifted students. She gave a group of participants a test of vocabulary that was aimed at the 7th-grade level. She quickly discovered that there was limited variability in the scores because nearly all the students answered 90% or more of the questions correctly. This outcome is called a _______ effect.