Refer to the Buena School District bus data.
a. Find the median maintenance cost and the median age of the buses. Organize the data into a two-by-two contingency table, with buses above and below the median of each variable. Determine whether the age of the bus is related to the amount of the maintenance cost. Use the .05 significance level.
b. Is there a relationship between the maintenance cost and the manufacturer of the bus? Use the breakdown in part (a) for the buses above and below the median mainte- nance cost and the bus manufacturers to create a contingency table. Use the .05 sig- nificance level.
c. Use statistical software and the .05 significance level to determine whether it is rea- sonable to assume that the distributions of age of the bus, maintenance cost, and miles traveled last month follow a normal distribution.