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

In the following study, participants were instructed to press a button on a computer keyboard as soon as they detected a tone through their headphones. Half of the time, the computer screen flashed a light at the exact moment the tone was presented and the other half of the time there was no flash of light. In addition, half of the time a sensor on the participant's arm pulsed (causing a slight tickle) at the exact moment of the tone, and half of the time the sensor did not pulse. The researchers were interested in determining the extent to which these distractions would cause participants to have delayed reaction times to the 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. Table 12-2 TAELE OF MEANS: ARM TICKLE TICKLE NO TICKLE ROW M Flash of Flash 784.60 627.60 706.10 Light No Flash 547.30 395.50 471.40 COLUMN M 665.95 511.55 $\text { Pop. } M = 588.75$ SOURCE TAELE SOURCE SS df MS F p Flash of Light Arm Tickle 550840.90 1 550840.90 223.79 .000 Light x Tickle 238393.60 1 238393.60 327.72 .000 Residual 67.60 1 67.60 0.02 .884 -Is this independent variable manipulated or measured?

Explain how a factorial design is different from a multiple-group design.

Is this a two-groups design, a multiple-groups design, or a factorial design? How do you know?

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. Which of the following is NOT an independent variable?

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 Participant Sex?

Lola conducts a study to examine aggression. She has both men and women come to a laboratory room that is either 70 degrees or 90 degrees. Suppose she finds that overall, participants exhibit more aggression in the 90-degree room than the 70-degree room. This finding illustrates a(n)

Questions refer to Table 12-4. A researcher is interested in determining just how much negative interactions with strangers affect our sense of well-being. In this example, participants completed a scale of positive affect. Later, either a pleasant or unpleasant confederate is randomly assigned to interact with each participant. At the end of the experiment, participants’ positive affect is again assessed. Positive affect scores could range from 1 (low positive affect) to 15 (high positive affect). Table 12-4 TABLE OF MEANS: TIME POSITIVE AFFECT ASSESSED BEFORE EXPERIMENT AFTER EXPERIMENT ROW M Confederate Pleasant 11.10 13.30 12.20 Demeanor Unpleasant 10.60 3.50 7.05 COLUMN M 10.85 8.40 Pop. =9.63 SOURCE TABLE SOURCE SS df MS F p Between subjects effects Confederate Demeanor 265.23 1 3705.63 420.43 .000 Error 158.65 18 8.81 Within subjects effects Time 60.03 1 60.03 18.14 .000 Confederate x Time 216.23 1 216.23 65.69 .000 Error 59.25 18 3.29 -Refer to Table 12-2. What is the dependent variable in this study?

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 -Is this independent variable manipulated or measured?

Suppose you conduct a factorial ANOVA for independent samples and for one of the main effects, the degrees of freedom are 1. How many groups exist for that independent variable?

In the boxes below, write in a pattern of means that would reveal a main effect of self-esteem. Humaristic Copritive-Behavioral Control Group High Self-Esteem M=10 M=10 M=10 Low Self-Esteern M=20 M=20 M=20

A researcher who conducts a series of experiments concerning a related topic is conducting

What is the difference between adding levels of an IV to a multiple-group design versus a factorial design? In your answer, discuss the number of groups that will get added in each case.

A significant interaction means that

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 possible interactions are there in this study?

Is this independent variable manipulated or measured?

A ________ table contains the results of an ANOVA.

If you conduct an experiment with one IV that has four levels, you have used a(n) ___________ design, and if you conduct an experiment with two IVs that each have two levels, you have used a(n) _____________ design.

Statistical comparisons made between group means after finding a significant F ratio are known as _____________ comparisons.

Assume you have conducted a 3 x 3 ANOVA for independent samples and you have obtained a significant main effect for the first IV, no main effect for the second IV, and no interaction. What should you do next?

What is a three-way design? Give an example. How many main effects and interactions would be present in your experiment?