Question

The following data represent the results from an independent-measures experiment comparing three treatment conditions. Use a spreadsheet to conduct an analysis of variance with α=0.05α=0.05 to determine whether these data are sufficient to conclude that there are significant differences between the treatments.

Treatment A	Treatment B	Treatment C
12	12	16
12	11	18
12	13	15
11	14	17
13	15	19

F-ratio =
p-value =

The results obtained above were primarily due to the mean for the third treatment being noticeably different from the other two sample means. For the following data, the scores are the same as above except that the difference between treatments was reduced by moving the third treatment closer to the other two samples. In particular, 3 points have been subtracted from each score in the third sample.

Before you begin the calculation, predict how the changes in the data should influence the outcome of the analysis. That is, how will the F-ratio for these data compare with the F-ratio from above?

Treatment A	Treatment B	Treatment C
12	12	13
12	11	15
12	13	12
11	14	14
13	15	16

F-ratio =
p-value =

Answer 1

1)Applying ANOVA from excel: data-data analysis:

Source of Variation	SS	df	MS	F	P-value
Between Groups	70	2	35.00	19.0909	0.0002
Within Groups	22	12	1.83
Total	92	14

F ratio =19.0909 (please try 19.09 if required to 2 decimals)

p value =0.0002 (please try 0.000 if required to 3 decimals)

2)

Source of Variation	SS	df	MS	F	P-value
Between Groups	10	2	5.0000	2.7273	0.1056
Within Groups	22	12	1.8333
Total	32	14

F ratio =2.7273 (please try 2.73 if required to 2 decimals)

p value =0.1056 (please try 0.106 if required to 3 decimals)