Question: A trucking business concerned about the time it takes to get trucks unloaded. The manager decides to try and reduce the time it takes to unload by charging customers for the time that the truckers are idle, waiting for a truck bay to open up. Currently the waiting time averages 3.5 hours. After 3 months of the newly instituted charges he randomly samples 36 deliveries.

A. State the null and alternative hypothesis to determine whether the unloading time has declined.

B. For ? = 0.05, state the rule for rejecting the null hypothesis.

C. The sample of 36 has an average unloading time of 2.9 hours and S = 1.2 hours. What can the manager conclude about the average unloading time for all deliveries?

D. What kind of error could he be making?