matched pairs design by cmFSb53

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```									                Completely Randomized versus Matched Pairs Experiment

Comparing Hand Strength: Is the right hand generally stronger than the left in
right-handed people? You can crudely measure hand strength by placing a
bathroom scale on a shelf with the end protruding, then squeezing the scale
between the thumb below and the four fingers above it. The reading of the scale
shows the force exerted.” [BPS/page 198/problem 3.43]

1. Diagram a completely randomized experiment to compare the strength of the
right and left hands, using 10 right-handed people as subjects.

2. Diagram a matched pairs experiment to compare the strength of the right and
left hands, using 10 right-handed people as subjects.

3. Which of the two designs is appropriate? Why.

Completely Randomized Experiment
R
a
n
d
o
Average
Group 1            Measure left hand         left hand
m
(5)
Available                                                         measures
A
group of
s                                                                         Compare
patients (10)   s
i
averages
g                                                   Average
Group 2
n                         Measure right            right hand
(5)
m                            hand                   measures
e
n
t

R               Match Pairs Experiment
a
n
d                      Measure left hand
o    Group 1              first, then
(5)                                             For each
Available
m                         right hand
subject,
group of                                  sesecond                                        Compare
A                                                    subtract right
patients (10)    s                                                    hand from left         to zero
s                                                    hand and take
i                        Measure right
g    Group 2             hand first, then           average of that
n      (5)                  left hand               list of numbers
m
e
n
t

```
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