1. How many independent variables are in a 4 Â 6 factorial designs?
How many conditions (cells) are in this design?
2. What is the difference between a cell (condition) mean and the means used to interpret a main effect?
3. What is the difference between a complete factorial design and an incomplete factorial design?
4. Explain the difference between a two-way ANOVA and a three-way ANOVA.
5. Complete each of the following ANOVA summary tables. In addition, answer the following questions for each of the ANOVA summary tables:
a. What is the factorial notation?
b. How many conditions were in the study?
c. How many subjects were in the study?
d. Identify significant main effects and interaction effects.
|
Source
|
df
|
ss
|
ms
|
F
|
|
|
A
|
1
|
60
|
|
|
|
|
B
|
2
|
40
|
|
|
|
|
A X B
|
2
|
90
|
|
|
|
|
Error
|
30
|
|
|
|
|
|
Total
|
35
|
390
|
|
|
|
|
Source
|
df
|
ss
|
ms
|
F
|
|
|
A
|
2
|
40
|
|
|
|
|
B
|
3
|
60
|
|
|
|
|
A X B
|
6
|
150
|
|
|
|
|
Error
|
72
|
|
|
|
|
|
Total
|
83
|
400
|
|
|
|
|
Source
|
df
|
ss
|
ms
|
F
|
|
|
A
|
1
|
10
|
|
|
|
|
B
|
1
|
60
|
|
|
|
|
A X B
|
1
|
20
|
|
|
|
|
Error
|
36
|
|
|
|
|
|
Total
|
39
|
150
|
|
|
|
6. A researcher is attempting to determine the effects of practice and gender on a timed task. Participants in an experiment are given a computerized search task. They search a computer screen of various characters and attempt to find a particular character on each trial. When they find the designated character, they press a button to stop a timer. Their reaction time (in seconds) on each trial is recorded. Subjects practice for 2, 4, or 6 hours and are either female or male. The reaction time data for the 30 subjects appear here.
|
2 Hours
|
Women
|
Men
|
|
2 Hours
|
12
|
11
|
|
|
13
|
12
|
|
|
12
|
13
|
|
|
11
|
12
|
|
|
11
|
11
|
|
4 Hours
|
Women
|
Men
|
|
4 Hours
|
10
|
8
|
|
|
10
|
8
|
|
|
10
|
10
|
|
|
8
|
10
|
|
|
7
|
9
|
|
6 Hours
|
Women
|
Men
|
|
6 Hours
|
7
|
5
|
|
|
5
|
6
|
|
|
7
|
8
|
|
|
6
|
6
|
|
|
7
|
8
|
|
Source
|
df
|
ss
|
ms
|
F
|
|
Gender
|
|
0.027
|
|
|
|
Practice
|
|
140.60
|
|
|
|
Gender X Practice
|
|
0.073
|
|
|
|
Error
|
|
28.00
|
|
|
|
Total
|
|
168.70
|
|
|
a. Complete the ANOVA summary table. (If your instructor wants you to calculate the sums of squares, use the preceding data to do so.)
b. Are the values of Fobt significant at . = .05? At . = .01?
c. What conclusions can be drawn from the F-ratios?
d. What is the effect size, and what does this mean?
e. Graph the means.
2. Explain the difference between multiple independent variables and multiple levels of independent variables. Which is better?
3. What is blocking and how does it reduce "noise"? What is a disadvantage of blocking?
4. What is a factor? How can the use of factors benefit a design?
5. Explain main effects and interaction effects.
6. How does a covariate reduce noise?
7. Describe and explain three trades-offs present in experiments.