Question

3	6	4	8	1
10	2	9	11	12
15	22	3	6	7
5	8	1	12	14

Each column represents a different treatment given to sick rats. Each cell is a different rat. Use statistical analysis and use post hoc testing using contrasts to find the best treatment.

Treatment 1: vitamins

Treatment 2: prescription pills

Treatment 3: brain surgery

Treatment 4: shock therapy

Treatment 5: dietary changes

Answer 1

Anova: Single Factor
SUMMARY
Groups	Count	Sum	Average	Variance
Column 1 ( vitamins )	4	33	8.25	28.91666667
Column 2 ( prescription pills )	4	38	9.5	75.66666667
Column 3 ( brain surgery )	4	17	4.25	11.58333333
Column 4 ( shock therapy )	4	37	9.25	7.583333333
Column 5 ( dietary changes )	4	34	8.5	33.66666667
ANOVA
Source of Variation	SS	df	MS	F	P-value	F crit
Between Groups	72.7	4	18.175	0.577289571	0.683540644	3.055568
Within Groups	472.25	15	31.4833333
Total	544.95	19

Since we see that P-value of ANOVA test>0.05 so there is insufficient evidence that the 5 treatments are not all equal. Hence we can conclude that these 5 treatments are equally effective. Therefore we do not need to perform post hoc test.