1. Consider the database performance problem. You would like to estimate
   the mean wait time of transactions to a level of accuracy of 1.5s. 
   You select a small sample of transactions and discover that the standard
   deviation is 10s. Determine the minimum sample size required in each
   case below.

   a) The required level of confidence is 90%. 
   b) The required level of confidence is 99%. 

2. Consider the CTI graduates problem. Let us say a journalist publishes
   an education column where he states that DePaul CTI graduates receive,
   on average, a starting salary of $55000 on graduation. The Dean sees
   this report and disagrees. He believes that CTI graduates receive better
   offers than the journalist claims and asks you to investigate.

   a) Identify and state the null and alternative hypotheses.
   b) You discover from a random sample of 26 recent CTI graduates that the
      mean starting salary is $58000 with standard deviation $4000. Given
      your hypotheses for part a above, conduct a test of significance.

3. A local company assembles customized workstations. The quality assurance 
   department monitors the quality of components from suppliers by selecting 
   random samples from each delivered batch and then rigorously testing each 
   component in the batch. The chief quality assurance engineer is interested 
   in a large batch of recently delivered disk drives. She believes that the
   supplier is producing drives that are slower than the specifications
   stipulate (i.e. mean seek time of 10.0ms). 

   a) Identify and state the null and alternative hypotheses.
   b) The engineer examines a sample of 81 drives and discovers that the
      mean seek time of these drives is 10.15ms with standard deviation 
      0.90ms. Given your hypotheses for part a above, conduct a test of 
      hypotheses.
   c) Given your findings, do you think a point estimate for the parameter
      in question is appropriate. Justify your answer.