TABLE 7.6 Pilot data on left ventricular mass (LVM) in children from the Bogalusa Heart Study 4-year LVM (g) Change (g)* ID Baseline LVM (g) 1 2 3 4 5 6 7 8 9 10 Mean sd 139 134 86 98 78 90 102 73 93 162 105.5 29.4 *4-year LVM minus baseline LVM 7.57 Implement the test in Problem 7.56 and provide a two-tailed p-value. 7.58 Provide a 95% CI for the change in LVM over 4 years based on the data in Table 7.6. 163 126 142 96 111 108 167 82 77 172 124.4 35.2 24 -8 56 -2 33 18 65 9 -16 10 18.9 26.4 7.59 Since this was a pilot study, the main question of interest is how many subjects would be needed to detect an increase of 10 g in mean LVM over 4 years using a two- sided test with α = 0.05 and power = 80%? Hint: Assume that the estimated variance of change in LVM in the pilot study is the true variance of change in LVM.
TABLE 7.6 Pilot data on left ventricular mass (LVM) in children from the Bogalusa Heart Study 4-year LVM (g) Change (g)* ID Baseline LVM (g) 1 2 3 4 5 6 7 8 9 10 Mean sd 139 134 86 98 78 90 102 73 93 162 105.5 29.4 *4-year LVM minus baseline LVM 7.57 Implement the test in Problem 7.56 and provide a two-tailed p-value. 7.58 Provide a 95% CI for the change in LVM over 4 years based on the data in Table 7.6. 163 126 142 96 111 108 167 82 77 172 124.4 35.2 24 -8 56 -2 33 18 65 9 -16 10 18.9 26.4 7.59 Since this was a pilot study, the main question of interest is how many subjects would be needed to detect an increase of 10 g in mean LVM over 4 years using a two- sided test with α = 0.05 and power = 80%? Hint: Assume that the estimated variance of change in LVM in the pilot study is the true variance of change in LVM.
MATLAB: An Introduction with Applications
6th Edition
ISBN:9781119256830
Author:Amos Gilat
Publisher:Amos Gilat
Chapter1: Starting With Matlab
Section: Chapter Questions
Problem 1P
Related questions
Question
Please only answer 7.59
Transcribed Image Text:TABLE 7.6 Pilot data on left ventricular mass (LVM) in
children from the Bogalusa Heart Study
4-year LVM (g)
Change (g)*
ID
12345678
Baseline LVM (g)
9
10
Mean
sd
139
134
86
98
78
90
163
126
142
96
111
108
167
24
-8
56
102
73
93
162
105.5
29.4
*4-year LVM minus baseline LVM
7.57 Implement the test in Problem 7.56 and provide a
two-tailed p-value.
7.58 Provide a 95% CI for the change in LVM over 4 years
based on the data in Table 7.6.
82
77
172
124.4
35.2
-2
33
18
65
9
-16
10
18.9
26.4
7.59 Since this was a pilot study, the main question of
interest is how many subjects would be needed to detect
an increase of 10 g in mean LVM over 4 years using a two-
sided test with α = 0.05 and power = 80%? Hint: Assume
that the estimated variance of change in LVM in the pilot
study is the true variance of change in LVM.
Transcribed Image Text:Cardiovascular
Disease, Pediatrics
Left ventricular mass (LVM) is an important risk factor for
subsequent cardiovascular disease. A study is proposed to
assess the relationship between childhood blood pressure
levels and LVM in children as determined from echocar-
diograms. The goal is to stratify children into a normal bp
group (< 80th percentile for their age, gender, and height)
and an elevated bp group (≥ 90th percentile for their age,
gender, and height) and compare change in LVM between
the 2 groups. Before this can be done, one needs to dem-
onstrate that LVM actually changes in children over a 4-year
period.
To help plan the main study, a pilot study is conducted
where echocardiograms are obtained from 10 random chil-
dren from the Bogalusa Heart Study at baseline and after 4
years of follow-up. The data are given in Table 7.6.
7.56 What test can be used to assess if there is a change
in mean LVM over 4 years?
Expert Solution
Step 1
Given information:
The data is given below.
| Change(g) |
| 24 |
| -8 |
| 56 |
| -2 |
| 33 |
| 18 |
| 65 |
| 9 |
| -16 |
| 10 |
| Mean= 18.9 |
| sd=26.42 |
d=10
α=0.05
1-ß=0.80
σ=26.42
Find: Sample size (n)
Formula to find sample size.
Step by step
Solved in 2 steps with 2 images
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