William H. Knapp III

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This homework was due on Friday, November 30 at 06:00 a.m. Turkish time. Late submissions receive half credit.

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1. What does it mean when we say we have a repeated measures anova?
It means we have repeated observations.
It means we have repeated observations for each condition.
It means we have repeated observations for each participant.

2. Why would anyone want to use a repeated measures ANOVA instead of an independent measures ANOVA?
It should decrease the size of the degrees of freedom for the Effect Term.
It should decrease the size of the degrees of freedom for the Error Term.
It should decrease the size of the Sum of Squares in the Effect Term.
It should decrease the size of the Sum of Squares in the Error Term.
It should increase the size of the degrees of freedom for the Effect Term.
It should increase the size of the degrees of freedom for the Error Term.
It should increase the size of the Sum of Squares in the Effect Term.
It should increase the size of the Sum of Squares in the Error Term.

3. Why would someone not want to use a repeated measures ANOVA?
It should decrease the size of the degrees of freedom for the Effect Term.
It should decrease the size of the degrees of freedom for the Error Term.
It should decrease the size of the Sum of Squares in the Effect Term.
It should decrease the size of the Sum of Squares in the Error Term.
It should increase the size of the degrees of freedom for the Effect Term.
It should increase the size of the degrees of freedom for the Error Term.
It should increase the size of the Sum of Squares in the Effect Term.
It should increase the size of the Sum of Squares in the Error Term.

4. Imagine you have a two-way 2X3 ANOVA with 8 observations per condition. How many degrees of freedom do you have for the effect of the first factor?

5. Imagine you have a two-way 2X3 ANOVA with 8 observations per condition. How many degrees of freedom do you have for the error when testing the effect of the first factor?

6. Imagine you have a two-way 2X3 ANOVA with 8 observations per condition. How many degrees of freedom do you have for the interaction between the two factors?

7. Imagine you have a two-way 2X3 ANOVA with 8 observations per condition. How many degrees of freedom do you have for the error when testing the interaction between the two factors?

8. Imagine you have a two-way repeated-measures 2X3 ANOVA with 8 observations per condition. How many degrees of freedom do you have for the effect of first factor?

9. Imagine you have a two-way repeated-measures 2X3 ANOVA with 8 observations per condition. How many degrees of freedom do you have for the error when testing the effect of first factor? HINT: If you know how to calculate the degrees of freedom for the independent ANOVA, you know how to do it for the repeated measures ANOVA.

10. Imagine you have a two-way repeated-measures 2X3 ANOVA with 8 observations per condition. How many degrees of freedom do you have for the interaction between the two factors?

11. Imagine you have a two-way repeated-measures 2X3 ANOVA with 8 observations per condition. How many degrees of freedom do you have for the error when testing the interaction between the two factors?

12. Imagine you have a two-way repeated-measures 2X3 ANOVA with 8 observations per condition. How many different error terms are there?

13. This is the second homework that involves real data from a real experiment. Get the data, save it, set your working directory and load the data into R. Feel free to look back at the last homework if you want more information about the different factors. Here' is a quick summary of the data we'll be dealing with today.
RT: Response Times, the dependent variable.
TP: Target Presence
DS: Display Size
ET: Encoding Time
QQ: Cue type
SS: Subject
Perform a one-way ANOVA investigating the effect of encoding time. What's the value of the F statistic?

14. Perform a one-way repeated-measures ANOVA investigating the effect of encoding time. What's the value of the F statistic? WARNING! When we do RM ANOVAS for fewer factors than are in the data set, like we're doing here, we'll have some residuals left over. Normally this would be an indication that something is wrong. We will ignore this here because I want you to practice doing ANOVAs with and without repeated measurements. If the data were more realistic we would only have one observation per subject instead of several. Rather having you load up multiple data sets for one homework assignment, or adding a whole bunch more subject variables, or having you learn some new functions, I thought doing these atypical analyses would be acceptable.

15. Perform a two-way ANOVA investigating encoding time, display size, and their interaction. What's the p-value for the interaction between the two factors?

16. Perform a two-way repeated-measures ANOVA investigating encoding time, display size, and their interaction. What's the p-value for the interaction between the two factors?

17. Perform a three-way ANOVA investigating encoding time, display size, cue type, and their interactions. What's the value of the F statistic for the interaction between the three factors?

18. Perform a three-way repeated-measures ANOVA investigating encoding time, display size, cue type, and their interactions. What's the value of the F statistic for the interaction between the three factors?

19. Perform a four-way ANOVA investigating encoding time, display size, cue type, target presence, and their interactions. What's the value of the F statistic for the interaction between the four factors?

20. Perform a four-way repeated-measures ANOVA investigating encoding time, display size, cue type, target presence, and their interactions. What's the value of the F statistic for the interaction between the four factors? IMPORTANT! After you finished this analysis, compare the values you found for the one-, two-, and three-way repeated measures ANOVAs with the values here.