Reference no: EM13251073
Q 1. How many independent variables are in a 4 x 6 factorial design? How many conditions (cells) are in this design?
Q 2. What is the difference between a cell (condition) mean and the means used to interpret a main effect?
Q 3. What is the deference between a complete factorial design and an incomplete factorial design?
Q 4. Explain the difference between a two-way AMOVA and a three-way ANOVA.
Q 5. Complete each of the following ANOVA summary tables. In addition, answer the following questions for each of the ANOVA summary
a. What is the factorial notion?
b. How many conditions were in the study
c. How many subjects were in the study?
d. Identify the significant main effects and interactions 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
Q 6. A researcher is attempting to determine the effects of practice and gender on a timed task. Participants in and experiment are given a computerized search task. They search computer screen of various characters and attempt to find a particular character on each trail. When they find the designated character they press a button to stop a timer. Their reaction time (in seconds) on each trail is recorded. Subjects practice for 2, 4, or 6 hours and are either female of male. The reaction time data for the 30 subjects appear here.
Women Men
2 Hours 12 11
13 12
12 13
11 12
11 11
4 Hours 10 8
10 8
10 10
8 10
7 9
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.
b. Are the values of Fobt significant at a = 05?
At a = .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.
Q 7. A 4 x 6 factorial design has to two independent variables. Thus, there is the possibility of two main effects (one for each independent variable) and one interaction effect (the interaction between the two independent variables)
a. This is 2 x 3 design.
Gender Raw Means
Practice Female Male (Practice)
1 hour 1,778.125 1,763.375 1,770.75
2 hour 1,512.375 1,764.25 1,638.31
3 hours 1,182.75 1,662 1,422.38
Column 1,491.08 1,729.88
means
(gender)
b. Two-way ANOVA Summary Table
Source df SS MS F
Factor A 1 684,264 684,264 9.68
(gender)
Factor B 2 989,504 494,752 7.00
(practice)
A x B 2 489,104 244, 552 3.46
Error 42 2,967,768 70,661.143
Total 47 5,130,640
c. Gender: F(1, 42) = 9.68, p < .01
Practice: F(2,42) = 7.00, p < .01
Interaction: F(2, 42) = 3.46, p < .05
d. The significant main effect of gender indicates that females preformed more quickly than males. The significant main effect of the practices that of practice indicates that as the amount of time spent practicing increased, reaction time decreased. The significant interaction effect indicates that practice affected only females; the more females increased practiced, the more quickly they responded. However, practice did not affect males; reactions times, for males were consistent across the various practice conditions.
e. Eta-squared was .13 for gender, .19 for practice, and .095 for the interaction. Thus, overall the proportion of variance in the dependent variable accounted for by the independent variables is .415 or 41.5%.
Q 8. Explain the difference between multiple independent variables and multiple levels of independent variables. Which is better?
Q 9. What is blocking and how does it reduce "noise"? What is a disadvantage of blocking?
Q 10. What is a factor? How can the use of factors benefit a design?
Q 11. Explain main effects and interaction effects.
Q 12. How does a covariate reduce noise?
Q 13. Describe and explain three trade-offs present in experiments.