Math 151 , Day 20, Wednesday, March 14, 2001

Exam 2 Day 24, the Friday of the week we return

Ch. 3.2
Questions on HW
Fancier designs (not "completely randomized") Control extraneous variability by presorting individuals into  homogeneous groups.
Matched pairs: To compare Control and experimental treatments (i.e. 2 levels)
   Sort experimental units into "matching" pairs.   One member of pair gets control, other gets experimental.
                Randomize which.
        Compare within pair, then summarize all comparisons.
  Common: Do the control and experiment to same individual (matched with self). (Randomize order)
        Are right feet bigger than left feet?       Sunburn salve?
    Aside:  Sampling data, "longitudinal study" following same people through time.
            Works like matched pair to control variability.
Block design:  Sort experimental units into "Blocks" = groups homogeneous on potentially confounding variables
     e.g. M/F, age, income, weight...
    Within each block, randomize the treatments. Compare results  within each block, then summarize all results.
    (Matched pairs is a special case of block design--each pair is a "block".)

Statistical Significance p.194: Day19

Toward Inference: Table p. 210, Exploratory Data Analysis vs. Statistical Inference

Will do Friday: Sec. 4.1:
                    Population  Choose from it a Sample (varies)
Calculate
Numerical summary:    Parameter (Greek letter)    Statistic (Latin)

The actual value of the Statistic will vary, depending on the particular sample. "Sampling variability"
The Statistic "estimates" the Parameter.  We hope it is close to the parameter.  If we choose simple random samples, we can understand the pattern of values the statistic can take.

Chance  behavior (a random phenomenon): Unpredictable in the short run,  predictable regular pattern in the long run.
 "Probability" of particular something happening: proportion of times it would happen in a very long series of repetitions of the phenomenon.


Final version: HWDay20, ReRead section  3.2, Matched pairs and block design; review ch. 3. Read P.210.
    Next: We'll do 4.1, 2, 3.  Skip 4.4 and Skip Ch. 5.
Hand in: 
Matched pairs and blocks 
p. 199 3.43 hand strength
3.45 weight loss
3.44 student traders.  The difference in the treatments is whether or not they have software that can make "charts" of past "trends." (If they don't have the software they don't have "charts")
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 Significance p. 195 3.40 
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p. 216, 4.4 spinning penny  bring in # of heads, #of spins, proportion 
         (If you plan to be absent Friday, please do this, email me result.)  
To be assigned Friday, Day 21 p. 215, 4.1, 2, 3 parameter, statistic		 Read, to discuss 

p. 209 3.72 McDonald's vs Wendy's
 

 p. 209 3.71speeding the mail
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p. 209 3.74 
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 Optional 
(more of same) 
p. 203, 3.58 
3.59
 
 

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