Problem Set 6 Solutions

1. In an experiment designed to determine the effect of mood on perception of pain, subjects were induced to experience a good mood, a bad mood, or had no mood induction. Participants were then asked to rate the amount of pain they were currently experiencing. Below is a list of the pain ratings. Test the null hypothesis that mood has no effect on perception of pain. (35 points)

  

Negative Mood

Positive Mood

Control Group

 

10

2

5

 

6

2

6

 

11

7

4

 

12

5

5

 

8

1

7

Research Problem:

Statistical Hypotheses:

Decision Rule:

Use Jamovi to calculate the F value and post hoc tests if warranted. Copy and paste your outputs here or upload a separate file with your outputs to the assignment in Blackboard. 

Decision:

Interpretation:

2. In a study of group productivity, participants worked alone or shared the responsibility for building widgets with one other, with three others, or with fifteen others. Below, are the data showing the number of widgets each group produced. Test the null hypothesis that group size had no effect on productivity. (35 points)

  

Alone

Two-person group

Four-person group

Sixteen-person group

 

9

8

4

5

 

10

6

6

8

 

12

5

3

3

 

9

6

6

6

Research Problem:

Statistical Hypotheses:

Decision Rule:

Use Jamovi to calculate the F value and post hoc tests if warranted. Copy and paste your outputs here or upload a separate file with your outputs to the assignment in Blackboard. 

Decision:

Interpretation:

3. Consider the following scores in an experiment involving three conditions;

A B C

2 5 8

2 5 8

2 5 8

2 5 8

Without actually computing the sum of squares within, what must its value be?

Why? (12 points)

4. Insert the missing entries in the summary table for a one-way analysis of variance having three levels of the independent variable and n = 25. (Each answer is 3 points)

Source  SS df MS F

Between     

Within  121 

Total 141