Power, Sample Size, Effect Size: Considerations for Research

[Pages:30]Power, Sample Size, Effect Size: Considerations for Research

Carol B. Thompson JH Biostatistics Center SON Brown Bag ? November 20, 2012

Research Approaches

? Comparisons ? statistical hypotheses ? Estimates ? precision (confidence intervals)

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Population vs Research Views

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Type I and Type II Errors (Which is Worse Risk?)

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Related Parameters for Prospective Analysis

? Effect Size ? Sample Size ? ? Power (1-)

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Parameters for and

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 vs

? doesn't rely on any of the other parameters ? or power relies on 3 parameters (N, , ES)

? Which relate to a specific HA

? For same sample size and ES, lower higher

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Comparing Two Means

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