Homework Assignment #13 Two-Way ANOVA

OkunNAME:______

Homework Assignment #13 Two-way ANOVA

A study is done in which 30 males low in hostility and 30 males high in hostility participate in a laboratory study (Factor C). Within each of the hostility groups, participants are randomly assigned to work on a task in which his partner praises him, criticizes him, or does not comment on his work (Factor R). After the task is completed, the pulse rate of each participant is recorded.

1 [C]. The data from this study should be analyzed using ______. In this analysis, there are __ independent variable(s) and __ dependent variable. The factors are ______and ______. The first factor (C) has ___ levels and the second factor (R) has ___ levels. The dependent variable is ______.

2 [C]. What null hypotheses should be tested in analyzing these data?

______

3 [C].Complete the following ANOVA summary table for these data.

______

SourceSSdfMSF

______

Between133 ___

Factor C______

Factor R 52 ______

Interaction 26 ______

Within______

Total 835 ___

4 [O]. What will be the critical value associated with each F ratio assuming alpha = .05?

Factor C: df = ( , ); CV = .

Factor R: df = ( , ); CV = .

CxR Interaction: df = ( , ); CV = .

5 [O]. What decision should you reach with respect to each null hypothesis?

______

6 [O].In light of your decisions, what follow up procedures should be carried out with respect to each effect?

7. [O] Which effect has priority? Why?

8. [C]In a 2 x 2 design, A researcher reports that Factor C has a significant effect on the dependent variable, Factor R has a significant effect on the dependent variable, and the effect of Factor C on the dependent variable is the same across the levels of Factor R. What does this tell you about the interaction effect?

9 [C]. You have conducted a two-way ANOVA with factors of teaching method (computer versus lecture) and semester (fall versus spring). The dependent variable is total number of test points earned during the semester. The F for Teaching Method was significant with a mean of 320 for students taught by computer and a mean of 280 for students taught by lecture. The effect for semester and the teaching method by semester interaction effect were not significant. What should you do next?

A.Conclude that the computer was more effective than lecture

B.Carry out a protected t-test on the teaching method means

C.Conclude that students learn more in the fall than in the spring semester

D.Conclude that the effect of teaching method varies with semester

10 [C]. The results of a two-way ANOVA on college satisfaction revealed that there was a significant effect due to Sex (1 and 70 dfs), a non-significant effect due to University (4 and 70 dfs), and a non-nsignificant Sex by University interaction effect(4 and 70 dfs). Which of the following do you know to be true?

A. Males scored higher than females

B. The sex difference was no larger than expected from random sampling from the same population

C. The sample size was 70

D. Sex differences vary across Universities

E. There were 5 universities in the study

11 [C]. In a two-factor ANOVA, the two factors were Ethnicity (Anglo versus Hispanic) and Movie (Beethoven, Balto, Bingo, or Benji). The dependent variable is ratings of how much the children liked the movie. The dfs within groups is 56. How many children were in the study? ______

Use the information in the statement below to answer questions 12 through 15.

Using a two-way ANOVA design, a social psychologist wishes to study the effects of being reared in an urban versus rural environment and having 0, 1, or 2 older siblings on parental attachment in adolescence. The data in the table represent the cell means for parental attachement scores.

Mean Parental Attachment Scores for the Various Combinations of Early Living Environment and Number of Older Siblings

Factor C

Number of Older Siblings

0 1 2

Factor R

Rural 62136

Early Living Environment

Urban21 2121

12 [C]. Which type of means (cell, row or column) are associated with the interaction effect?

13 [C].How can you make a preliminary determination of whether an interaction effect is likely to be found? What do you conclude from doing this?

14 [C].Which means is associated with the effect of Factor C? What are the values of these means?

15 [C].Which means is associated with the effect of Factor R? What are the values of these means?

16 [O]. A researcher conducts a study in which she manipulates the arousal level of participants (low, medium, or high) and the difficulty of the task (easy or hard). Summary information on scores on the task is provided below.

AROUSAL LEVEL

LowMedium High

Easy N=5N=5N=5N=15

X=15X=30X=45X=90

TASK DIFFICULTYM=3M=6M=9M=6

SS=18SS=28SS=26

Hard N=5N=5N=5N=15

X=5X=20X=5X=30

M=1M=4M=1M=2

SS=8SS=20SS=20

N=10N=10N=10N=30

X=20X=50X=50X=120

M=2M=5M=5M=4

A. What null hypotheses should be tested in analyzing these data?

______

B.Complete the following ANOVA summary table for these data.

______

SourceSSdfMSF

______

Between

Factor C

Factor R

Interaction

Within

Total

C [O]. What will be the degrees of freedom and critical value associated with each F ratio assuming  = .05?

Factor C: df = ( , ); CV = .

Factor R: df = ( , ); CV = .

CxR Interaction: df = ( , ); CV = .

D [O]. What decision should you reach with respect to each null hypothesis?

______

E [O]. Carry out the appropriate follow up procedures for Factor C.

F. [C}. Which effect has priority? Plot the appropriate means associated with this effect and provide a written description of the effect.