Math 151 , Spring 2008 Friday Day 21, March 14 Hit reload....after class.

HW:  (Re) read:  Chapter 8.  Read p. 200 (Other designs) last (optional).  Check p. 206, 8.17-22, 26 at first., then 8.23-25 with Table B.  Ahead, Chapter 9.

Hand in Monday after break:
Producing Data
p. 192, 8.1, 8.2, 8.3 expt, obsn
p. 207, 8.27 Alcohol & heart attacks

p. 194, 8.4, 5, 6 population/sample
. . . . . .
p. 195, 8.7 Sampling badly on campus
- - - - - - -
p. 199 8.10 Minority Managers Use the Simple Random Sample Applet, and choose a sample of size 6. Give your answer by listing their names. (I believe that everyone will get different samples.) Five of the 28 managers have East Asian surnames:  Huang, Kim, Liao, Shen, Wang.  How many of these are in your sample?  

 Postpone the rest ?YES
p. 199 8.9 Apartment living, SRS. Use Table B.
p. 209, 8.36 Area code sample, SRS  Use Table B.
p. 211, 8.45 random digit dialing
p. 210, 8.41 random digit characteristics p.209-10, 8.38 b only Traffic lights
p. 208, 8.30 movie viewing
+ + + + + + + +
p. 205, 8.16, Ask more people
p. 212, 8.50, Polling Hispanics

 Read, to discuss 

p. 208, 8.29 safety of anesthetics
p. 192 8.3 TV & aggression (lurking)

.p.195, 8.8 more Sampling badly on campus
- -Postpone - -
p. 211, 8.47 guns

p. 204, 8.14, 8.15 biases.
p. 208, 8.31 world affairs
p. 211, 8.46 wording survey questions

p. 212, 8.49 Canada healthcare

 Optional 


Postpone
p. 209, 8.35 Use table B (more practice)

p. 209, 8.34 seat belt use

Exam results:   Comments & more   Solutions
   Some are fine, but many had much difficulty with Normal Tables.  They will return!

Finishing Ch. 5:   Homework questions?
Revisit r2:   Day 16 (didn't do this Wed.)
(sum of squared residuals / sum of squared dev's from y-bar) = proportion of variability in y's NOT explained by regression line on x.
 r2 =  1 - (sum of squared residuals / sum of squared dev's from y-bar) = proportion of variability which IS explained by regression line on x.

Cautions: Day 19
     Plot the data:   summary numbers (r, line) not resistant; only measure linear.
      Extrapolation--beware. Relationship may not persist outside range of data.
     "Lurking" variable:  has an important effect, but not one of the variables studied.

Association does not imply causation Day 19

+ + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + +
New:

Chapters 1 through 5 have covered analyzing data that was given to us--what it said about itself.
    Informally, develop guesses, suspicions, hypotheses about the world the data came from.
From Exploration to Inference p. 186

Ch. 8&9:  Producing Data:  Aim:  create data sets that will allow us to make inferences to a larger world than just the data we have.   Details Day 20

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