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Sample Size Calculations for Clustered and Longitudinal Outcomes in Clinical Research
book

Sample Size Calculations for Clustered and Longitudinal Outcomes in Clinical Research

by Chul Ahn, Moonseoung Heo, Song Zhang
December 2014
Intermediate to advanced content levelIntermediate to advanced
260 pages
8h 51m
English
Chapman and Hall/CRC
Content preview from Sample Size Calculations for Clustered and Longitudinal Outcomes in Clinical Research
16 Sample Size Calculations for Clustered and Longitudinal Outcomes
If σ
2
1
= σ
2
2
= σ
2
, then the required sample size per group is
n =
2σ
2
(z
1α
+ z
1β
)
2
2
. (1.6)
In some randomized clinical trials, more subjects are assigned to the treat-
ment group than to the control group to encourage participation of subjects
in a trial due to their higher chance of being randomized to the treatment
group than the control group. Let n
1
= n be the number of subjects in the
control group and n
2
= kn be the number of subjects in the treatment group.
Then, the sample size for the study will be
n
1
= n = (1 + 1/k)σ
2
(z
1α
+ z
1β
)
2
2
. (1.7)
The total sample size for the trial is
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Publisher Resources

ISBN: 9781466556270