Plans for Chapter 8
                         Statistical Inference

Chapter objectives:  Be able to understand and extrapolate from poll data.  
Learn how to find the standard deviation/standard error for a simple random 
sample of size n and for an average of n things, and how to apply these 
formulas.  Show how confounding can arise unexpectedly in data analysis.
   
Day 1:
     Review the basics of percents.  Stress the difference between number and 
     percent.  Watch approximately the first 12 minutes of tape #10, Statistical
     Inference.  Stop with the discussion of the relation of sample size to 
     confidence interval in the Bureau of Labor Statistics unemployment survey.
     Discuss the meaning of the terms parameter and statistic - point out that 
     parameters like p are usually unknown, but can be estimated by statistics 
     like p hat.

     Assignment: read pp. 309-323 and do p. 333 #1, 2, 3, 4

Day 2:
     Recall (from the video) the related formulas for the standard deviation of 
     the results from a random sample and for the standard error.  Point out 
     that a real poll using a multi-stage random sample will have a little 
     different standard error.  Discuss confidence intervals using recent 
     examples of polls from the paper.  Point out that since polls usually 
     report results with 95% confidence, that 1 out of 20 polls will be off by
     more than the stated interval, but only 0.3% will be off by more than 1.5 
     times their confidence interval, and virtually none should be off by twice      their confidence interval, unless there's a flaw in the poll (which may 
     or may not be due to deliberate bias).

     Assignment:  read pp. 323-329, do 1 and 2 on sheet M8b, and pp. 333-334 # 
     5, 6, 7, 9.

Day 3:
     Watch the rest of tape #10.
     Contrast the estimation of population proportion and population means.  Do 
     problem #19, page 335 in detail for the class.  Have the students try 
     problem 3 on M8b and see the distinction between it and the first two 
     problems.

     Assignment: Read pages 329-331, do pp. 336-337 # 22, 23, 27.

Day 4:
     Go over the perils of data analysis by using sheets M8d1, M8d2, and M8d3.  
     Have the students work in groups of 3.  In each group have one student 
     with each of the sheets try to decide which hospital they should go to.  
     Then have them jointly make the decision. 
     Allow time for class discussion - they won't all believe that two rights 
     can add up to a wrong at first!

     Assignment: do pp. 339-340 # 35, 37.