Question

The A-Z pharmaceutical company has developed a new anti-anxiety drug (anxiolytic) Feelssogood. To test its effectiveness on anxiety versus 4 other common anxiolytics (Valium, Xanax, Buspar, and Lorazepam), 20 rats were randomly assigned to one of the five drug conditions and placed in an elevated plus maze. The maze has two “open arms” and two “closed arms.” Since rats are nocturnal animals, and generally avoid lighted areas, it is thought that anxiety-reducing drugs reduce the fear of exploring the “open arms.” The amount of time spent in the open arms per 15 minute test session after administration of each of the drugs is presented below.

Drug
Feelssogood	Valium	Xanax	Buspar	Lorazepam
2	4	7	5	4
3	7	7	4	5
6	9	12	7	9
2	3	6	2	3

Are the drugs different in their effectiveness in reducing anxiety at the .05 level? Complete a 6-step hypothesis test at the .05 level.

Answer 1

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

H0: μ1 = μ2 = μ3 = μ4 =μ5, Drugs are same in their effectiveness in reducing anxiety

H1: Drugs are different in their effectiveness in reducing anxiety

ANOVA - Single Factor
Alpha	0.05
Groups	Count	Sum	Mean	Variance
Column 1	4	13	3.25	3.58
Column 2	4	23	5.75	7.58
Column 3	4	32	8	7.33
Column 4	4	18	4.5	4.33
Column 5	4	21	5.25	6.92
Source of Variation	SS	df	MS	F	P-value	F critical
Between Groups	49.3	4	12.33	2.07	0.14	3.06
Within Groups	89.25	15	5.95
Total	138.55	19

p-value (Significance F) = 0.14

Since p-value is more than 0.05, we do not reject the null hypothesis and conclude that the 5 dugs are same in their effectiveness in reducing anxiety.