Instructions: Answer each question, and when required explain your answer. Your explanation must be clear and complete. You may refer to your book, your notes and your homework papers.
  1. Problems 15 and 16 on p. 712.
  2. Suppose ACT scores in a particular year are approximately normally distributed with mean 20 and standard deviation of 6.
  3. An American Research Group poll of a nationwide random sample of 2,104 likely voters was conducted by telephone March 2-5, 2007. It showed Clinton 42% and McCain 45% (with 10% Undecided). Determine a 95% confidence interval for the 45% McCain figure. Show how you compute your answer.