Question

A regional package delivery company is considering changing from full-size vans to SUV’s. The company sampled SUV’s from each of four manufacturers. The number sampled represents the number of SUV’s the manufacturer was able to provide for the test. Each SUV was driven for 10,000 miles, and the operating cost per mile (in cents) was computed.

Part of the data (operating cost per mile, in cents) and partial Excel output are provided below.

SUV 1	SUV 2	SUV 3	SUV 4
13.6	12.4	?	12.5
?	13.4	12.1	?
13.6	?	15.2	15.1
?	12.5	?	?
14.3	?	14.8	12.2
12.8	14.6	13.5	12.9
?	12.6
13.2

SUMMARY
Groups	Count	Sum	Average	Variance
SUV 1	8	110.4	13.80	0.428571429
SUV 2	7	91.7	13.10	0.586666667
SUV 3	6	84	14.00	1.24
SUV 4	6	80.7	13.45	1.283
ANOVA
Source of Variation	SS	df	MS	F
Treatments	?	?	?	?
Error	?	?	0.831956522
Total	22.29407407	?

Construct a 95% confidence interval estimate of the mean difference in operating cost per mile (in cents) between SUV 3 and SUV 4. (Negative values must include the minus sign. Report your answers to 2 decimal places, using conventional rounding rules)

________ ≤ (µ_{SUV 3} - µ_{SUV 4}) ≤ ______

Answer 1

ANOVA
Source of Variation	SS	df	MS	F
Treatments	3.159074064	3	1.053025	1.26572082
Error	19.13500001	23	0.831957
Total	22.29407407	26