Refer to the Buena School District bus data.

a. Select the variable for the number of miles traveled last month. Conduct a test of hypothesis to determine whether the mean number of miles traveled is equal to 840. Use the .01 significance level. Find the p-value and explain what it means.

b. Using the maintenance cost variable, conduct a test of hypothesis to determine whether the mean maintenance cost is less than $500 at the .05 significance level. Determine the p-value and interpret the result.

c. Suppose we consider a bus "old" if it is more than eight years old. At the .01 significance level, can we conclude that less than 40% of the buses are old? Report the p-value.