College stats A NOVA

College stats A NOVA you can skip question 25-30.

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65-040 Computer-Assisted Data Analysis

Part I: Identifying appropriate the statistical test.

Questions

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– 6. A new medicine, BeGone, claims to relieve a headache in ten minutes and last for up to six hours. Researchers running a clinical trial to test BeGone’s effectiveness assessed headache relief, as measured by self-report on a scale of 1 (no relief) to 10 (complete relief); specifically they were interested in whether there was significant difference in headache relief given BeGone treatment as compared to a placebo or no treatment at all. They tested three separate groups of people – those who had a headache and took BeGone, those who had a headache and took a placebo, and those who had a headache but took nothing.

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Points

Question

Enter your response in the space below:

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1. What is (are) the research hypothesis/es of the clinical study?

2. What is (are) the null hypothesis/es of the clinical study?

3. What is the dependent variable?

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4. List the independent variable(s) and the levels of the IV(s). State (for each IV), whether it is between- or within-Ss.
5. Which test would be appropriate to analyze the data in this study?				☐one-way independent groups ANOVA ☐one-way repeated measures ANOVA ☐two-way independent groups ANOVA ☐two-way repeated measures ANOVA ☐two-way mixed measures ANOVA
6. State whether the researchers should look for an interaction effect. If so, please draw a graph of a possible interaction that the researcher might observe and describe the interaction you have depicted.

Questions 7 – 12. Researchers were interested in whether there was a significant difference in the effectiveness of biological gestures (e.g., pointing) in divert attention as compared to directional icons (e.g., arrows) or directional words (e.g., left) and whether the effect (if any) is significantly mediated by the length of time the directional cue is presented. Suppose the researchers asked study participants to move their eyes in the opposite direction of a directional cue and recorded how long it took participants to initiate a correct eye movement.

F

or one group of participants, the cue remained on the screen until the eye movement was initiated, while for a separate group of participants, the cue was simply flashed for a tenth of a second. Both groups were presented with all possible cues – biological, iconic, and words.

(This example is based on a real paper, amusingly called “Giving subjects the eye and showing them the finger”, Gregory and Hodgson, 2012.)

Points

Question

Enter your response in the space below:

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7. What is (are) the research hypothesis/es of the experimental study?

8. What is (are) the null hypothesis/es of the experimental study?

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☐one-way independent groups ANOVA
☐one-way repeated measures ANOVA
☐two-way independent groups ANOVA
☐two-way repeated measures ANOVA
☐two-way mixed measures ANOVA

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9. What is the dependent variable?

10. List the independent variable(s) and the levels of the IV(s). State (for each IV), whether it is between- or within-Ss.

11. Which test would be appropriate to analyze the data in this study?

12. State whether the researchers should look for an interaction effect. If so, please draw a graph of a possible interaction that the researcher might observe and describe the interaction you have depicted.

Questions 13 – 18. Researchers were interested in the effect of Lent on the diet of hyenas who scavenge food from the local human population. They tested the percent of donkey meat ingested in a single population of hyenas before, during, and after Lent. The researchers were interested in whether there was a significant difference in the amount of donkey meat ingested as a function of the time period relative to Lent.

(This is also based on a real study! See here for gripping details about how the researchers knew what the hyenas were eating: http://www.sciencedaily.com/releases/2012/04/120405075232.htm)

Points

Question

Enter your response in the space below:

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13. What is (are) the research hypothesis/es of the observational study?

14. What is (are) the null hypothesis/es of the observational study?

15. What is the dependent variable?

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☐one-way independent groups ANOVA
☐one-way repeated measures ANOVA
☐two-way independent groups ANOVA
☐two-way repeated measures ANOVA
☐two-way mixed measures ANOVA

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16. List the independent variable(s) and the levels of the IV(s). State (for each IV), whether it is between- or within-Ss.

17. Which test would be appropriate to analyze the data in this study?

18. State whether the researchers should look for an interaction effect. If so, please draw a graph of a possible interaction that the researcher might observe and describe the interaction you have depicted.

Questions 19 – 24. Researchers are interested in whether there is a significant difference in the reduction of anxiety in geriatric patients with dementia following cognitive-behavioral therapy as compared to psychoanalytic treatment, and whether the effect (if any) is significantly mediated by gender. They randomly assigned men and women to either cognitive-behavior therapy or psychoanalytic therapy, and evaluated patients’ improvement using the Beck Anxiety Inventory (BAI).

Points

Question

Enter your response in the space below:

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19. What is (are) the research hypothesis/es of the observational study?

20. What is (are) the null hypothesis/es of the observational study?

21. What is the dependent variable?

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☐one-way independent groups ANOVA
☐one-way repeated measures ANOVA
☐two-way independent groups ANOVA
☐two-way repeated measures ANOVA
☐two-way mixed measures ANOVA

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22. List the independent variable(s) and the levels of the IV(s). State (for each IV), whether it is between- or within-Ss.

23. Which test would be appropriate to analyze the data in this study?

24. State whether the researchers should look for an interaction effect. If so, please draw a graph of a possible interaction that the researcher might observe and describe the interaction you have depicted.

Part II: Carrying out a two-way mixed model ANOVA using SP

SS

.

Carry out an analysis using SPSS for the study above that you identified as the two-way mixed design ANOVA.

Points

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Enter your response in the space below each question:
			3	25. Make up your own data for the two-way mixed model ANOVA and enter it into SPSS. Create a clustered bar graph and copy and paste it below.
26. Describe the main effects and interaction as they are shown in your graph. (It may help you to generate separate graphs for each of the main effects.)

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Points

Question

Enter your response in the space below:

Extra Credit +2

☐yes
☐no

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27. Run a two-way mixed design ANOVA using SPSS and copy and paste the following output tables: Mauchly’s Test of Sphericity, Tests of Within -Subjects Effects, and Tests of Between-Subjects Effects.
	Extra Credit +2	28. Was Mauchly’s Test of Sphericity found to be significant?		☐yes ☐no
29. Should you look to the Greenhouse-Geisser corrected value for the significance of the main effect of the within-Ss variable?
30. Write a short paragraph reporting the results of the main effects and interaction. For each, you must report the F value, the relevant degrees of freedom, and the significance level.

Part III: Computing a two-way independent groups ANOVA by hand.

Researchers have found that healthy people demonstrate faster simple reaction times than people suffering from a common cold. This raises the possibility that drivers who are sick are more likely to get into car accidents and be injured in other situations requiring quick responses. Researchers are interested in whether sucking on a cough drop containing menthol may be a cheap and non-invasive way to boost alertness and reaction times.

A research team runs a pilot study containing only 16 participants. Participants were randomly assigned to one of two

Health

conditions. The eight participants in the

Sick

condition agreed to have a cold virus placed in their noses, which resulted in them getting a cold. The other eight participants were

Healthy

. During a simple reaction time test, half of the participants in each condition sucked on a

Cough Drop

containing

Menthol

; the other half sucked on a Cough Drop containing

Pectin

.

The researchers expected (a) to replicate the previous finding that Healthy people would show faster reaction times than Sick people. Furthermore, they hypothesized that (b) people who sucked on a cough drop containing Menthol would show faster reaction times than people who sucked on a cough drop containing Pectin, and (c) that the difference in reaction times would be greater for Sick people than for Healthy people.

They collected the following data:

Healthy

Pectin

Healthy

Pectin

Healthy

Healthy

Menthol

Healthy

Menthol

Pectin

Sick

Pectin

Sick

Pectin

Sick

Menthol

Sick

Menthol

Sick

Menthol

	Health	CoughDrop	ReactionTime
							Healthy								Pectin	225
260
275
							Menthol	280
210
265
							Sick	420
375
480
340
320
310

31. Describe the main effect (if any) of Health in the bar graph below (1 pt):

32. Describe the main effect (if any) of Cough Drop in the bar graph below (1 pt):

33. Describe the interaction (if any) between Health and Cough Drop in the bar graph below (1 pt):

34. Fill in the cell and marginal means of the contingency table (3 pts). (You do not need to show your work for these means.)

Pectin

Menthol

Health

Healthy

Sick

Overall Average

Cough Drop		Overall Average

35. Figure and :

a. Please show your work in the table below (5 pts):

Healthy, Pectin	Healthy, Menthol

Sick, Pectin

Sick, Menthol

In order to get credit for (b) and (c) below, you must show your work (e.g., show what numbers you are adding, subtracting, etc.).

b. (2 pts)

c. (2 pts)

36. Figure and :

a. Please show your work in the table below (5 pts):

Healthy

Sick

In order to get credit for (b) and (c) below, you must show your work (e.g., show what numbers you are adding, subtracting, etc.).
b. (2 pts)
c. (2 pts)

37. Figure and :

a. Please show your work in the table below (5 pts):

Pectin

Menthol

In order to get credit for (b) and (c) below, you must show your work (e.g., show what numbers you are adding, subtracting, etc.).
b. (2 pts)
c. (2 pts)

38. Figure and :

a. Please show your work in the table below:

In order to get credit for (b) and (c) below, you must show your work (e.g., show what numbers you are adding, subtracting, etc.).
b. (2 pts)
c. (2 pts)

39. Figure F’s for the main effects and the interaction.

In order to get credit for (a) through (c) below, you must show your work.

a. (2 pts) Rows

b. (2 pts) Columns

c. (2 pts) Interaction

40. Determine F cutoffs:

a. (2 pts) Rows (Health)

b. (2 pts) Columns (Cough Drop)

c. (2 pts) Interaction (Health x Cough Drop)

41. Fill in the ANOVA summary table below (5 pts).

Source	SS	df	MS	F	p
Sleep
Gender
Sleep X Gender
Within (Error)
Total

42. Write a short paragraph reporting the results of the main effects and interaction. For each, you must report the F value, the relevant degrees of freedom, and the significance level. (3 pts)

43. Which of the researchers’ hypotheses were supported? (2 pts)

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