MA 123 Quiz 2
Fall, 2011

Name:  _________________________________________________

1. (10 pts total) Andy, Belle, Christy, Doug, Elie, Frank, Gina, Horace and Ida have volunteered to participate in a study concerning eating habits of senior citizens.   The researchers plan to form three groups of subjects from the volunteers and expose each group to one of three different treatments (numbered 1, 2, and 3).
   
   
   1. (6 pts) Use a random process to form three groups, by first assigning each volunteer a single digit number, then using Table B in the textbook (pp T-4 & T-5) to select digits randomly.  Start at the first digit in the leftmost column of digits in row 140.  Be sure to write down which number you assign to each volunteer, and write down which people are assigned to which groups. Feel free to use initials only to refer to volunteers.
      
      
      
      
      
      
      
      
   2. (2 pts) What is the best way to avoid bias in choosing a treatment for each group?
      
      
      
      
      
      
      
   3. (2 pts) How could this study be made to be double-blind?
      
      
      
      
      
      
      

2. (10 pts total) Three separate coins are tossed.  Each coin is fair; i.e., it is equally likely to come up heads or tails.

   1. (3 pts) What is the sample space S for this random phenomenon?
      
      
      
      
      
   2. (3 pts) What is the event E that two of the three coins come up heads?
      
      
      
      
      
   3. (2 pts) What is the probability P(E) that two of the three coins come up heads?
      
      
      
      
      
   4. (2 pts) What is the probability for the event that none of the three coins come up heads?