Chapter 6: Estimation and Confidence Intervals

Answers for all ‘Test Yourself’ questions from the book to check your performance and widen your overall understanding of the contents.

  1. No, this is not an appropriate conclusion.  The population mean either is or is not between those values; computing a confidence interval does not change that.
    1. 0.84
    2. 2.457
  3. The mean production rate is a point estimate, and it is much easier to interpret.  The confidence interval is an interval estimate, and although it is more difficult to interpret, it provides information about the precision of that estimate.  If you want the benefits of both, report both!
  4. You should only calculate the confidence interval using the t-distribution if you cannot determine the population standard deviation (or standard error).  The z-distribution version is always preferable to the t-distribution version if you know this parameter.
    1.  245
    2.  31
    3.  542