Question

Answer the following question based on your observations of the SPSS output file:

Looking at the descriptives (first information), do you see differences in the mean alcohol contents for the three levels of quality? Explain.

Descriptives
Alcohol by Volume (in %) for brand
	N	Mean	Std. Deviation	Std. Error	95% Confidence Interval for Mean
					Lower Bound	Upper Bound
VeryGood	11	4.9000	.17889	.05394	4.7798	5.0202
Good	14	4.6000	.38829	.10377	4.3758	4.8242
Fair	10	4.5100	.34140	.10796	4.2658	4.7542
Total	35	4.6686	.35295	.05966	4.5473	4.7898

Descriptives
Alcohol by Volume (in %) for brand
	Minimum	Maximum
VeryGood	4.70	5.20
Good	4.00	5.50
Fair	3.90	5.00
Total	3.90	5.50

1.420

2

32

.256

ANOVA
Alcohol by Volume (in %) for brand
	Sum of Squares	df	Mean Square	F	Sig.
Between Groups	.906	2	.453	4.357	.021
Within Groups	3.329	32	.104
Total	4.235	34

Answer 1

From ANOVA table we see that P-value=0.021<0.05 so there is a significant evidence that the mean alcohol contents for the three levels of quality are all not same.

Again 95% CIs for "VeryGood" and "Good" are not completely disjoint so there is an evidence that means of these two levels are not significantly different. Similarly means of levels "Good" and "Fair" are not significantly different. Whereas   95% CIs for "VeryGood" and "Fair" are completely disjoint so there is an evidence that means of these two levels are significantly different.