Question

Integrative Part B: ANOVAs

Integrative B 1

A researcher is interested in whether the emotional content and presentation method of a story affect memory for components of the story. Participants read a positive, neutral or negative story; memory for the story is measured by the number of story components correctly recalled in a 5-minute period. Participants either listen to the story on an MP3 player, or read the story text on a tablet.

The design uses independent samples, with n = 9 per cell.

a. Fill in the following source table. (NOTE: You do NOT need to show work for each blank you fill in.)

***TO FILL IN BLANKS: Copy and paste the entire table into the text box. Then fill in each of the 20 blanks provided.

Source	SS	df	MS	F obs	F crit
Between-groups	___	___	XXX	XXX	XXX
Presentation Method	48	___	___	___	___
___	___	___	12	___	___
___	___	___	75	___	___
Within-groups	____	___	___	XXX	XXX
Total	750	___	XXX	XXX	XXX

b. For each effect, indicate whether or not the effect is significant at an alpha of .05 (state "yes" or "no" for each effect).

Answer 1

a.

Source	SS	df	MS	F obs	Fcrit
Between-groups	222	5	XXX	XXX	XXX
Presentation Method	48	1	48	4.363636	4.04
Emotional content	24	2	12	1.090909	3.19
Presentation Method x Emotional content	150	2	75	6.818182	3.19
Within-groups	528	48	11	XXX	XXX
Total	750	53	XXX	XXX	XXX

a = Number of levels of Presentation Method = 2

b = Number of levels of Emotional content = 3

df Presentation Method = a - 1 = 2 - 1 = 1

df Emotional content = b - 1 = 3 - 1 = 2

df Presentation Method x Emotional content = (a - 1) * (b -1) = 1 * 2 = 2

df Between-groups = 1 + 2 + 2 = 5

df Total = abn - 1 = 2 * 3 * 9 - 1 = 53

df Within = ab(n-1) = 2 * 3 * (9-1) = 48

MS and SS are filled for each source based on the formula.

MS = SS / df

df Between-groups = 48 + 24 + 150 = 222

SS Within = SS Total - SS Between = 750 - 222 = 528

For each source, F obs = MS / MS Within

Critical value of F at 0.05 significance level and df = 1, 48 is 4.04

Critical value of F at 0.05 significance level and df = 2, 48 is 3.19

b.

Since F obs > F crit for Presentation Method and Presentation Method x Emotional content ,

Presentation Method is significant at alpha of 0.05.

Presentation Method x Emotional content   is significant at alpha of 0.05.

Emotional content is not significant at alpha of 0.05.