Fundamentals of Biostatistics
8th Edition
ISBN: 9781305268920
Author: Bernard Rosner
Publisher: Cengage Learning
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Anemia (low healthy blood cells or hemoglobin) has an important role in exercise performance.
However, the direct link between rapid changes of hemoglobin and exercise performance is
still unknown. A study investigated 18 patients with a blood disorder (beta-thalassemia).
Participants in the study performed an exercise test before and the day after receiving a blood
transfusion. Data are given in the table.
HB = Hemoglobin
RER = Respiratory exchange
ID
Change in
HB
Obese
RER > 1.1
ratio
No
No
1
-1.4
No
-1.5
No
Yes
No
Yes
3
-2
No
4
-2.1
No
-1.9
Yes
Yes
No
-1.6
-1.8
-0.8
6
7
No
Yes
No
Yes
8
9.
-1
No
No
-1.2
No
Yes
10
11
No
No
-0.8
-1.5
12
Yes
No
No
Yes
13
14
-1.4
-2.6
-1.7
No
No
Yes
Yes
15
Yes
No
Yes
Yes
16
-2.6
No
17
18
-2.7
-1.5
No
Passive exposure to environmental tobacco smoke has been associated with growth suppression and
an increased frequency of respiratory tract infections in normal children. Is this association more
pronounced in children with cystic fibrosis? To answer this question, 43 children (18 girls and 25
boys) attending a 2-week summer camp for cystic fibrosis patients were studied (New England Journal
of Medicine, Sept. 20, 1990). Among several variables measured were the child's weight percentile
(y) and the number of cigarettes smoked per day in the child's home (x).
a. For the 18 girls, the coefficient of correlation between y and x was reported as r = –.50. Interpret
-
this result.
b. Refer to part a. The p-value for testing Ho: p = 0 against H;: p # 0 was reported as p = .03.
n Interpret this result.
c. For the 25 boys, the coefficient of correlation between y and x was reported asr = -.12. Interpret
%3D
%3D
this result.
d. Refer to part c. The p-value for testing Ho: p = 0 against Ha: p #…
In 2007, a university study was published investigating the crash risk of alcohol impaired driving.
Data from 2,871 crashes were used to measure the association of a person’s blood alcohol level (BAC) with the risk of being in an accident. The table below shows results from the study.
BAC
0
.01
.03
.05
.07
.09
.11
.13
.15
.17
.19
.21
risk
1
1.03
1.06
1.38
2.09
3.54
6.41
12.6
22.1
39.05
65.32
99.78
a. Find the best fit exponential model for the risk of having an accident based on your BAC.
b. Use your model to predict the relative risk of having an accident for a person with a BAC of 0.08 which is the legal limit in GA.
c. What BAC would make you 50 times more likely to have an accident than someone who has not been drinking?
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