Pain tolerance study. A study published in Psychosomatic Medicine (March/April 2001) explored the relationship between reported severity of pain and actual pain tolerance in 337 patients who suffer from chronic pain. Each patient reported his/her severity of chronic pain on a 7-point scale (1 = no pain, 7 = extreme pain). To obtain a pain tolerance level, a tourniquet was applied to the arm of each patient and twisted. The maximum pain level tolerated was measured on a quantitative scale.
(a) According to the researchers, ‘‘correlational analysis revealed a small but signi?cant inverse relationship between [actual] pain tolerance and the reported severity of chronic pain.'' Based on this statement, is the value of r for the 337 patients positive or negative?
(b) Suppose that the result reported in part a is signi?cant at α = .05. Find the approximate value of r for the sample of 337 patients. [Hint:
Use the formula t = r√(n - 2)//(1 - r2).]
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FEEDING TRIAL
1
|
DIET
Plants
|
WEIGHT CHANGE (%)
-6
|
DIGESTION EFFICIENCY (%)
0
|
ACID-DETERGENT FIBER (%)
28.5
|
|
2
|
Plants
|
-5
|
2.5
|
27.5
|
|
3
|
Plants
|
-4.5
|
5
|
27.5
|
|
4
|
Plants
|
0
|
0
|
32.5
|
|
5
|
Plants
|
2
|
0
|
32
|
|
38
|
Duck Chow
|
9
|
59
|
8.5
|
|
39
|
Duck Chow
|
12
|
52.5
|
8
|
|
40
|
Duck Chow
|
8.5
|
75
|
6
|
|
41
|
Duck Chow
|
10.5
|
72.5
|
6.5
|
|
42
|
Duck Chow
|
14
|
69
|
7
|