Table 2.

Power analysis of patient and control groups

Sample Size: X-Sectional, Cohort, & Randomized Clinical Trials
Two-sided significance level (1-alpha):			95
Power (1-beta, % chance of detecting):			80
Ratio of sample size, Unexposed/Exposed:			1
Percent of Unexposed with Outcome:			35
Percent of Exposed with Outcome:			65
Odds Ratio:			3.5
Risk/Prevalence Ratio:			1.9
Risk/Prevalence difference:			30
	Kelsey	Fleiss	Fleiss with CC
Sample Size-Exposed	44	43	49
Sample Size-Nonexposed	44	43	49
Total sample size:	88	86	98

CC = continuity correction. Results are rounded up to the nearest integer. Print from the browser menu or select, copy, and paste to other programs. Results from OpenEpi, Version 3, open source calculator-SS Cohort. Print from the browser with ctrl-P. Or select text to copy and paste to other programs.