Exam 12: Designing, Conducting, Analyzing, and Interpreting Experiments With Multiple Independent Variables

Is this a between-groups design, a within-groups design, or a mixed design? How do you know?

Sandy conducts a study with two independent variables: one is an independent groups IV and the other is a repeated measures IV. Sandy has used _________ assignment.

A factorial design in which both IVs involve random assignment is referred to as a __________ factorial design.

Describe in words the pattern of results depicted in these data (you do not need to include any statistics).

Draw a block diagram of this experiment and label it completely.

Kyle is interested in examining how sex of participant (male, female) and self-esteem (high, low) affect perseverance on a novel task. What is the dependent variable in this study?

Suppose instead, you obtained the following data: Marning Testing Afternoon Testing Older Adults =15 =15 Yourger Adults =19 = -Does there appear to be an interaction between age and time of day? (Hint: Draw a line graph)

Examine Table 1 on p. 896 of the article. Draw a line graph depicting these means and then explain the interaction in your own words.

Draw a block diagram of this experiment and label it completely.

Is this a between-groups design, a within-groups design, or a mixed design? How do you know?

Which of the following is NOT one of the main types of experimental designs?

How did the authors measure perceived guilt of the defendant? What is the scale of measurement for this variable?

Suppose a researcher is interested in examining the effects of sex of participant, sex of confederate, and self-esteem of participant (high, low) on the participants' reactions to negative feedback. How many separate groups are involved in this between-groups study?

What is the shorthand notation for this experiment? (for example, 2 x 3, 2 x 2 x 2, etc.) Explain your answer.

In the following study, male and female participants were instructed to press a button on a computer keyboard as soon as they detected a tone through their headphones. Participants were randomly assigned to hear either a loud tone or a soft tone. The researchers measured the amount of time it took participants to press the computer button (in milliseconds). Smaller numbers indicate better performance on the task. TAELE OF MEANS: TONE INTENSITY LOUD SOFT ROW M Participant Female 516.70 834.50 675.60 Sex Male 528.80 763.80 646.30 COLUMN M 522.75 799.15 $\text { Pop. } M = 660.95$ SOURCE TAELE -What are the degrees of freedom for the Intensity x Participant Sex interaction?

Describe in words the pattern of results you created in the above question (you do not need to include any statistics).

If there is a significant interaction in a factorial design, why do researchers typically ignore (or minimize the importance of) the main effects?

Suppose you were interested in conducting an experiment with two independent variables. Why should you use a factorial design instead of two separate experiments?

Example #1: A researcher wishes to examine whether time of day (morning versus afternoon) affects the memory of older and younger participants. He obtains a sample of 40 older individuals and 40 younger individuals and gives them a passage to read. They are later given a test over the passage (scores on the test could range from 0 to 30). Half of the individuals are randomly assigned to read the passage and take the test in the morning, and the other half do so in the afternoon. The data are reported in the table below (the numbers represent mean test scores for each group). Marning Testing Afternoon Testirg Older Adults =15 = Yourger Adults =16 = -Name the dependent variable.

What does it mean when results are "marginally significant?" What is the relationship between marginal significance and Type I errors?