Question

A trucking fleet-owner owns two semi-trucks and wishes to compare the amount of fuel used per week by the two vehicles. In a random sample of 100 weeks, truck #1 used a mean volume of 330 gallons with a standard deviation of 12 gallons. In a second, independent random sample of 100 weeks, truck #2 used a mean volume of 316 gallons with standard deviation 10 gallons. It is of interest to construct a confidence interval for the difference in population means using a confidence level of 80 percent. ?1−?2, where ?1 is the mean fuel volume used by truck #1 and ?2 is the mean volume of fuel used by truck #2. Enter values below rounded to three decimal places.

(a) The estimate is: _____ gallons.

(b) The standard error is: _______gallons.

(b) The multiplier is: _______

Answer 1

a) The estimate is

b) The standard error is = 1.562 gallons

c) The multiplier is = 1.286