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Intro-Stat, Math 203 B, Quiz 3, March 1, 2001
  1. What is the difference between an observational study and an experiment?

    2.  

     
     
     
     
     
     
     

  2. List one weakness or problem with voluntary response sampling, and list one strength or positive aspect of random sampling.







  3. New varieties of corn with altered amino acid contents may have higher nutritional value than normal corn, which is low in the amino acid lysine. An experiment compares two new varieties of corn, opaque-2 and floury-2, with normal corn. The researchers mix corn-protein meal diets with each type of corn at two different protein levels, 12% protein and 18% protein. They feed each diet to 10 one day old male chicks and record their weights after 21 days. The chicks weight gain is a measure of the nutritional value of their diet. The researchers have 60 chicks for this experiment.
    1. What are the experimental units in this case?



    2. What is the response variable?




    3. List the factor(s) of this experiment, and the levels of each factor.







    4. How many groups would be needed for this experiment?






    5. Assuming all the groups have the same number of chicks in them, use Table B or randInt to select the first three groups of chicks.