The regional transit authority for a major metropolitan area wants to determine whether there is any relationship between the age of a bus and the annual maintenance cost. A sample of 10 buses resulted in the following data.
Age of Bus (years) Maintenance Cost ($)
1 ............. 350
2 ............. 370
2 ............. 480
2 ............. 520
2 ............. 590
3 ............. 550
4 ............. 750
4 ............. 800
5 ............. 790
5 ............. 950
a. Develop the least squares estimated regression equation.
b. Test to see whether the two variables are significantly related with α = .05.
c. Did the least squares line provide a good fit to the observed data? Explain.
d. Develop a 95% prediction interval for the maintenance cost for a specific bus that is 4 years old.