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Basic Science
intermediate
X-Type

Statistical Power and Sample Size - Power Analysis and Beta Error

Research Methodology and Statistics

A research team is designing a randomized controlled trial comparing a new fixation technique versus the standard technique for distal radius fractures. They expect the new technique to improve grip strength at 12 months by 15% compared to standard treatment. From previous studies, the standard deviation of grip strength is approximately 12 kg. They want to detect this difference with 80% power at a significance level of 0.05 using a two-sided test. Regarding statistical power and sample size determination:

Mark each as TRUE or FALSE

A

Statistical power is the probability of correctly rejecting a false null hypothesis (detecting a tru...

B

The four key determinants of sample size in a comparative study are: (1) significance level (alpha),...

C

Increasing sample size decreases statistical power; a smaller effect size requires fewer subjects to...

D

Effect size represents the magnitude of difference between groups expressed in standardized units; C...

E

An underpowered study may fail to detect a clinically important difference even if one exists (Type ...

Answer the questions to see explanations

Click T (True) or F (False) for each option