Group
Number of
Children
Mean PEF
Std Dev PEF
Chronic Bronchitis
25
281
68
No Chronic Bronchitis
25
319
74
Question 33
3.4 out of 3.4 points
A clinical trial is run to investigate the effectiveness of an experimental drug in
reducing preterm delivery to a drug considered standard care and to a placebo.
Pregnant women are enrolled and randomly assigned to receive either the
experimental drug, the standard drug or a placebo. Women are followed through
delivery and classified as delivering preterm (< 37 weeks) or not. The data are shown
below.

Preterm Delivery
Experimental Drug
Standard Drug
Placebo
Yes
17
23
35
No
83
77
65
Is there a statistically significant difference in the proportions of women delivering
preterm among the three treatment groups? Run the test at a 5% level of
significance.
Question 34
3.4 out of 3.4 points
A study is run comparing HDL cholesterol levels between men who exercise regularly
and those who do not. The data are shown below.
Regular Exercise
N
Mean
Std Dev
Yes
35
48.5
12.5
No
120
56.9
11.9
Generate a 95% confidence interval for the difference in mean HDL levels between
men who exercise regularly and those who do not.
Question 35
3.4 out of 3.4 points
Suppose a hypertension trial is mounted and 18 participants are randomly assigned
to one of the comparison treatments. Each participant takes the assigned medication

and his or her systolic blood pressure is recorded after 6 months on the assigned
treatment. The data are as follows.
Standard Treatment
Placebo
New Treatment
124
134
114
111
143
117
133
148
121
125
142
124
128
150
122
115
160
128
Is there a difference in mean systolic blood pressure among treatments? Run
the appropriate test at α = 0.05.
Question 36
3.4 out of 3.4 points
A study is designed to investigate whether there is a difference in response to
various treatments in patients with Rheumatoid arthritis. The outcome is the patient’s
self-reported effect of treatment. The data are shown below. Is there a significant
difference in effect of treatment? Run the test at a 5% level of significance.
Symptoms
Worsened
No Effect
Symptoms
Improved
Total
Treatment 1
22
14
14
50
Treatment 2
14
15
21
50
Treatment 3
9
12
29
50

Question 37
3.4 out of 3.4 points
Using the data below, suppose we focus on the proportions of patients who show
improvement. Is there a statistically significant difference in the proportions of
patients who show improvement between treatments 1 and 2. Run the test at a 5%
level of significance.
Symptoms
Worsened
No Effect
Symptoms
Improved
Total
Treatment 1
22
14
14
50
Treatment 2
14
15
21
50
Treatment 3
9
12
29
50
Question 38
0 out of 3.4 points
An analysis is conducted to compare mean time to pain relief (measured in minutes)
under four competing treatment regimens. Summary statistics on the four treatments
are shown below.
Treatment
Sample Size
Mean Time to Relief
Sample Variance
A
5
33.8
17.7
B
5
27.0
15.5
C
5
50.8
9.7
D
5
39.6
16.8

Complete the following ANOVA Table.
Source of
Variation
SS
df
MS
F
Between
Groups
.