Question

A researcher wanted to conduct a study to assess the influence of social exclusion on stress eating among African American women. In this study, participants played a computer-based simulated game of catch with 3 other participants in which the participants were either included or excluded and saw either African American or Caucasian faces. Specifically, the 20 participants were randomly assigned into 1 of the following 4 groups: Group 1 in which participants saw African American faces and were included, Group 2 in which participants saw Caucasian faces and were included, Group 3 in which participants saw African American faces and were excluded, and Group 4 in which participants saw Caucasian faces and were excluded. After playing the game for 5 minutes, participants were provided 130 grams of snack foods and were left alone for an additional 5 minutes. The data in the table below show the amount(s) of food (in grams) participants ate:

	Group 1	Group 2	Group 3	Group 4
	75	90	115	130
	55	80	110	125
	69	60	100	120
	73	75	113	128
	50	85	105	117
Total(s)	322	390	543	620

According to this data, is there a difference in the mean number of grams of food participants ate at a 5% level of significance?

a. Set up hypotheses and indicate level of significance

b. Indicate the appropriate test statistic

c. Set up decision rule

d. Compute the test statistic

e. Compute the overall mean and SSB

Answer 1

a) Null Hypothesis:Ho :μ_Group1 =μ_Group2 =μ_Group3 =μ_Group4

Alternate Hypothesis:Ha:Not all group means are equal

level of significance =0.05

b) appropriate test statistic is F_(3,16)

c) Decision rule: Reject HO if test statsitic F>3.239

D)applying ANOVA on above data:

Source of Variation	SS	df	MS	F
Between Groups	11225.35	3	3741.78	46.039
Within Groups	1300.40	16	81.28
Total	12525.75	19

test statistic F =46.039

e)overall mean =468.75

SSB =11225.35