Question

fleet manager wanted to determine the best replacement tires for their corporate automobiles. He selected six tire-types and had a set of each of them installed randomly on 23 selected automobiles. He then recorded the mileage when the tires came due for replacement. Use the Excel output below to analyze the data. Are there differences in life-time mileages of tires, at the five percent significance level?

ANOVA
Source of Variation	SS	df	MS	F	P-value	F crit
Between Groups		5	8217.22
Within Groups			1592.3
Total	68155.2	22

What is the critical value of the test statistic?

Round to four decimals.

Answer 1

Ho: there is no significant difference in the mean lifetime mileage of 6 tires types.

H1: at least one of the six tyre type differ significantly in the mean lifetime mileage.

ANOVA
Source of Variation	SS	df	MS	F	P-value	F crit
Between Groups	=8217.22*5	5	8217.22	=8217.22/1592.3	0.00463	2.8099962
Within Groups	=1592.3*17	=22-5	1592.3
Total	68155.2	22

ANOVA
Source of Variation	SS	df	MS	F	P-value	F crit
Between Groups	41086.1	5	8217.22	5.160597877	0.00463	2.8100
Within Groups	27069.1	17	1592.3
Total	68155.2	22

With F=5.156, P<5%,I reject the null hypothesis at 5% level of significance and conclude that at least one of the six tyre type differ significantly in the mean lifetime mileage