Question

answer

A researcher examines factors that affect thinking.  In one study, she had three groups of participants work on seven problems that required creative thinking.  One group prepared for the task by exercising; a second group watched a comedy video; the third group was a control group that simply began work on the problems.  The scores below show the number correct for each participant.  

Exercise	Comedy	Control
5	4	4
4	7	2
1	2	1
2	5	1
3	3	3
0	4	2
2	1	0

Select the correct statistical test; perform the test, and any subsequent post-hoc tests; report the results according to the handbook guidelines; explain what the results mean.

Answer 1

Using Excel, go to Data tab, select Data Analysis, choose Anova: Single Factor

ANOVA - Single Factor
Alpha	0.05
Groups	Count	Sum	Mean	Variance
Exercise	7	17	2.42857142857143	2.95238095238095
Comedy	7	26	3.71428571428571	3.9047619047619
Control	7	13	1.85714285714286	1.80952380952381
Source of Variation	SS	df	MS	F	P-value	F critical
Between Groups	12.6666666666667	2	6.33333333333333	2.19230769230769	0.140574263175222	3.55455714566179
Within Groups	52	18	2.88888888888889
Total	64.6666666666667	20

H0: μ1 = μ2 = μ3, Mean scores for the three factors are the same

H1: Mean score for at least one of the three factors is different

p-value (Significance F) = 0.141

Since p-value is more than 0.05, we do not reject the null hypothesis and conclude that mean scores for the three factors are the same. So, all the three factors have same effect on level of thinking.

Since there is no significant difference in means, there is no need to conduct a post-hoc test.