QUESTION

# 1. Which of the following would cause Fobt to increase?a. an increase in the difference between the means b. an increase in the within-groups variabilityc. an increase in the magnitude of

1.  Which of the following would cause Fobt to increase?

a.  an increase in the difference between the means

b.  an increase in the within-groups variability

c.  an increase in the magnitude of the independent variable’s effect

d.  a and c

2.  If dfB = 4 and df W = 11, using a = 0.05, Fcrit = ______.

a.  3.36             b.  4.60             c.  3.74             d.  3.48

4. Using the Fischer’s LSD test, if there are 16 df associated with MS within, and a = 0.05 and the number of groups = 3, the critical t we would use to calculate our critical difference is

a.  2.12             b.  3.00                         c.  3.65                         d.  4.79

5.  Using the Tukey test, if there are 20 df associated with MS within, and a = 0.05 and the number of groups = 5, Qcrit = ______.

a.  4.13                         b.  3.00                         c.  3.65                         d.  4.23

6. Using the Neuman Keuls test, if there are 16 df associated with MS within, and a = 0.05 and the number of groups = 6, what would be our Qcrit to evaluate means that are four steps apart?

a.  4.05                         b.  3.00                         c.  3.65                         d.  4.79

7. Using the Bonferroni t-test, if there are 16 df associated with MS within, and a = 0.05 and the number of comparisons we want to make is 5, the critical t we would use to calculate our critical difference is

a.  2.12             b.  3.00                         c.  3.65                         d.  2.92

(4 points)

Source                                  SS                      df                       MS                            F

Between Groups               203.333                   2                     101.667                       22.59

Within Groups                    54                        12                        4.5

8. Which of the numbers above represents the variability of the group means?

9. Which of the above numbers is the numerator of the average variance within the groups?

10. What is the critical F needed for significance given the situation above?

11. Assuming = cell frequencies, how many subjects in each group for the data above?

12. Consider the following graphic results from a 2 ´ 2 factorial experiment. These results most clearly show ____.

a.

there are no significant main effects or interaction effects

b.

there is a significant main effect for factor A, no other significant effects

c.

there is a significant main effect for factor B, no other significant effects

d.

there is a significant interaction effect, no other significant effects

____  13.   Consider the following graphic results from a 2 ´ 2 factorial experiment. These results most clearly show ____.

a.

there are no significant main effects or interaction effects

b.

there is a significant main effect for factor A, no other significant effects

c.

there is a significant main effect for factor B, no other significant effects

14. (17) points)  A clinical psychologist is interested in evaluating the effectiveness of the following three techniques for treating mild depression:  cognitive restructuring, assertiveness training, and an exercise/nutrition program. Forty undergraduate students suffering from mild depression are randomly sampled from the university counseling center’s waiting list and randomly assigned 10 each to the three techniques previously mentioned and the remaining 10 to a placebo control group.  Treatment is conducted for 10 weeks, after which depression is measured using the Beck Depression Inventory. The post-treatment depression scores are given here.  Higher scores indicate greater depression.

Treatment

Placebo

Cognitive restructuring

Assertiveness training

Exercise/nutrition

27

10

16

26

16

8

18

24

18

14

12

17

26

16

15

23

18

18

9

25

28

8

13

22

25

12

17

16

20

14

20

15

24

9

21

18

26

7

19

23

Conduct a one-way anova and copy and paste the output below.

Compute omega squared

Compute Cohen’s F below

Conduct subsequent tests show all of your work.

Tukey test

Tukey Critical Difference =

Tukey results:

Neuman Keuls Test

Neuman Keuls Critical Difference

NKCD4 =

NKCD3=

NKCD2=

Neuman Keuls Results

LSD Test

LSD Results

LSD=

Bonferroni Test

Bonferroni CD=

Bonferroni Results

15. (20 point)

The effects of smoking on human performance was investigated using three tasks that differed in the level of cognitive processing that was required to perform them, with different participants serving in each task.

Pattern recognition task - participants had to locate a target on a screen

Cognitive task - participants were required to read a passage and then recall it at a later time

Driving simulation video game

In each case the dependent variable was the number of errors that the participant committed.

Participants were further divided into three Smoking groups.

Group AS was composed of people who actively smoked during or just before carrying out the task.

Group DS participants were regular smokers who had not smoked for 3 hours before the task (D stands for delay).

Group NS were nonsmokers.

Pattern Recognition

NS:  9   8   12   10   7   10   9   11   8   10   8   10   8   11   10

DS:   12   7   14   4   8   11   16   17   5   6   9   6   6   7   16

AS:   8   8   9   1   9   7   16   19   1   1   22   12   18   8   10

NS:   27   34   19   20   56   35   23   37   4   30   4   42   34   19  49

DS:  48   29   34   6   18   63   9   54   28   71   60   54   51   25  49

AS:34  65   55   33   42   54   21   44   61   38   75   61   51   32  47

Driving Simulation

NS:  15   2   2   14   5   0   16   14   9   17   15   9   3   15   13

DS: 7   0   6   0   12   17   1   11   4   4   3   5   16   5   11

AS:3   2   0   0   6   2   0   6   4   1   0   0   6   2   3

Compute a 3 (Smoking Group) x 3 (Task) ANOV A.

a) copy and paste the anova table output below and answer the following questions

1. What number is the average variance in each group?_____________________

2. What number is the denominator of each of the F ratios?__________________

1. What number of df are used when looking up q values for doing Tukey tests.__________
1. What number reflects the variance of the 9 cell means that remains after we subtract the variance due to the two main effects._________
1. What is omega squared for the main effect of Task?_________________
1. What is omega squared for the main effect of Smoking Group?_________________
1. What is omega squared for the interaction og Task x Smoking  Group?_________________
1. What is Cohen’s F for the main effect of Task?_________________
1. What is Cohen’s F  for the main effect of Smoking Group?_________________
1. What is Cohen’s F  for the interaction of Task x Smoking  Group?_________________

11. Copy and paste below the test for Homogeneity of variance from the output. Do you have homogeneity of variance?How do you know?

We have heterogeneity of variance since levene’s test is significant.

12. If the main effect of Task is significant conduct subsequent Tukey tests and state what groups are different from each other. If no Tukey tests are needed than just state that.

3 x 3 x 15

Tukey Critical Difference=

Results of the Tukey Test: . (Tell me which means are =, < or > each other)

13. If the main effect of Smoking Group is significant conduct subsequent Tukey tests and state what groups are different from each other. If no Tukey tests are needed than just state that.

14. If the interaction of Task and Smoking Group is significant conduct subsequent Tukey tests to investigate to examine the simple effects of smoking group separately at each type of task. That is investigate smoking group differences for the pattern recognition task, for the Cognitive Task and for the Driving Task.

Pattern Recognition

Driving Simulation

Tukey Critical =

Tukey Results =

For the Pattern Recognition task tell me which means are =, < or > each other)

For the Cognitive task tell me which means are =, < or > each other.

For the Driving  task tell me which means are =, < or > each other.

1. Conclusions. (Be specific and be complete and use words).
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