For the preceding problem you should find that there are significant differences among the three treatments. One reason for the significance is that the sample variances are relatively small. The following data have the same sample means that appeared in the preceding question, but the SS values within each sample are doubled.

I	II	III
n = 6	n = 6	n = 6	N = 18
M = 1	M = 2	M = 6	G = 54
SS = 120	SS = 130	SS = 80	X = 576

Calculate the sample variance for each of the three samples.

I	II	III
s =	s =	s =

These values are the variances in the previous question (12.00, 13.00, and 8.00).

Predict how the increase in sample variance should influence the outcome of the analysis. That is, how will the F-ratio for these data compare with the value obtained in the previous problem?

Larger sample variances should the F-ratio.

Use an ANOVA with = .05 to determine whether there are any significant differences among the three treatment means.

Source	SS	df	MS	F	Fcriticalcritical
Between treatments
Within treatments
Total

F Distribution

Numerator Degrees of Freedom = 6

Denominator Degrees of Freedom = 16

0.01.02.03.04.05.06.07.08.09.010.011.012.0F

Conclusion:

Reject the null hypothesis; there are significant differences among the three treatments.

Reject the null hypothesis; there are no significant differences among the three treatments.

Fail to reject the null hypothesis; there are no significant differences among the three treatments.

Fail to reject the null hypothesis; there are significant differences among the three treatments.