Refer to the Buena School District bus data.
a. Conduct a test of hypothesis to reveal whether the mean maintenance cost is equal for each of the bus manufacturers. Use the .01 significance level.
b. Conduct a test of hypothesis to determine whether the mean miles traveled is equal for each bus manufacturer. Use the .05 significance level.
c. Develop a 95% confidence interval for the disparity in the average maintenance cost between buses made by Bluebird and Thompson.