STAT 207. ASSIGNMENT NO. 10

Read Chapter 10

Do the following problems:

10.1. Answer the questions in 10.1 in each of the 4 situations:

• n is small and sigma is known(assume data are normally distributed);
• n is small and sigma is unknown (assume data are normally distributed);
• n is large and sigma is known; and
• n is large and sigma is unknown.

10.7

10.8

Additional Problem: A major west coast city provides one of the most comprehensive emergency medical services in the world. Operating in a multiple hospital system with approximately 20 mobile medical units, the service goal is to be able to respond to medical emergencies with a mean time of 12 minutes (or less). The director of medical services want to formulate a hypothesis testing procedure that could use a sample of emergency response times to determine whether or not the service is meeting its 12 minute or less response goal.

1. What are the hypotheses that the director should consider?
2. In a sample of size 25, we obtained the following emergency response times (in minutes):

    14.0 16.3 11.0 14.6 15.0 12.0 12.5 13.9 13.7 
    13.2 11.2 14.2 13.2 14.0 11.9 13.4 11.8 13.9 
    14.2  9.3 12.9 13.4 13.1 11.3  8.9
   

   Use these data to test the hypotheses and make a sensible recommendation to the director.