Question

Use SPSS for this Application Exercise:
A pharmaceutical company tested three formulations of a pain relief medicine for migraine headache sufferers. Volunteers were selected and randomly assigned to one of the three drug formulations. The volunteers were instructed to take the drug during their next migraine headache episode and to report their pain on a scale of 1 to 10 (10 being most pain). The data are below. What can be concluded with ? = 0.05?

formulation A	formulation B	placebo
1 6 8 4 5 4 6 5 5 5 5	6 6 7 6 6 7 5 6 6 6 6	4 6 4 6 2 5 2 6 2 7 2

a) What is the appropriate test statistic?
---Select--- na one-way ANOVA within-subjects ANOVA two-way ANOVA

b) Compute the appropriate test statistic(s) to make a decision about H₀.
p-value =  ; Decision:  ---Select--- Reject H0 Fail to reject H0

c) Using the SPSS results, compute the corresponding effect size(s) and indicate magnitude(s).
?² =  ;  ---Select--- na trivial effect small effect medium effect large effect

d) Make an interpretation based on the results.

At least one of the formulations differ on pain.None of the formulations differ on pain.   

Answer 1

Tests of Between-Subjects Effects
Dependent Variable:Pain scale
Source	Type III Sum of Squares	df	Mean Square	F	Sig.
Corrected Model	20.424a	2	10.212	4.411	0.0209
Intercept	845.121	1	845.121	365.039	0.0000
Medicine	20.424	2	10.212	4.411	0.0209
Error	69.455	30	2.315
Total	935.000	33
Corrected Total	89.879	32

a) What is the appropriate test statistic?

Ans: one-way ANOVA.

b) Compute the appropriate test statistic(s) to make a decision about H0.
p-value = 0.0209 ; Decision: Reject H0 (Because the estimated p-value is less than 0.05 level of significance.)

c) Using the SPSS results, compute the corresponding effect size(s) and indicate magnitude(s).
?2 =  ;  ---Select--- na trivial effect small effect medium effect large effect

Ans: h2 = SSeffect / SStotal =20.424/89.879=0.2272.

d) Make an interpretation based on the results.

Ans: At least one of the formulations differ on pain.