radial tires instead of regular belted tires improves fuel economy.
Twenty cars were equipped with radial tires and driven over a
prescribed test course. Without changing drivers, the same cars
were then equipped with regular belted tires and driven once again
over the test course. The gasoline consumption for each type of
tire, in kilometers per liter, is presented in the attached R
file.
(a) On the same graph, draw boxplots for the gasoline
consumption of the cars with radial tires and the cars with belted
tires. Comment.
(b) Using normal-probability plots, check if the gasoline
consumption of the cars with radial tires and the cars with belted
tires are approximately normally distributed. Use 𝛼 = 0.10 for the
Anderson-Darling test of normality. Explain your answer.
(c) Construct a 97% confidence interval for the variance of the
gasoline consumption of the cars with radial tires.
(d) Construct a 97% confidence interval for the standard
deviation of the gasoline consumption of the cars with belted
tires.
(e) Construct a 97% confidence interval for the ratio of the
variances of the gasoline consumption of the cars with radial and
belted tires. Would you say it is reasonable assuming equal
variances?
(f) Drawn a conclusion for the equality of variances using a
p-value.
- A Taxi Company Manager Is Trying To Decide Whether The Use Of Radial Tires Instead Of Regular Belted Tires Improves Fuel 1 (11.83 KiB) Viewed 81 times