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Question 701
Statistics → Epidemiology
Classification
Question
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Statistical power
Question Stem
Investigators want to increase the ability of a study to detect a genuine clinically important difference. Which modification is most appropriate?
Options
A
Reduce the sample size
B
Increase the sample size
C
Increase the P value after analysis
D
Widen the confidence level after analysis
E
Replace the alternative hypothesis with the null hypothesis
Explanation
Statistical power is the ability of a study to detect a statistically significant difference when a genuine difference exists. Power increases with sample size, improving the ability to identify a clinically important effect when it is present.
Option Validity
A) reducing sample size generally reduces statistical power.
C) changing the P value after analysis is not a method of increasing study power.
D) altering the confidence level after analysis does not increase the underlying study power.
E) changing the wording of the hypotheses does not increase power.
Further Reading
Review statistical power and its relationship with sample size.