Power {epiDisplay} | R Documentation |
Calculation of power given the results from a study
power.for.2p(p1, p2, n1, n2, alpha = 0.05) power.for.2means(mu1, mu2, n1, n2, sd1, sd2, alpha = 0.05)
p1, p2 |
probabilities of the two samples |
n1, n2 |
sample sizes of the two samples |
alpha |
significance level |
mu1, mu2 |
means of the two samples |
sd1, sd2 |
standard deviations of the two samples |
These two functions compute the power of a study from the given arguments
Virasakdi Chongsuvivatwong <cvirasak@medicine.psu.ac.th>
'n.for.2means', 'n.for.2p'
# Suppose, in the example found in 'help(n.for.2p)', # given the two proportions are .8 and .6 and the sample size # for each group is 60. power.for.2p(p1=.8, p2=.6, n1=60, n2=60) # 59 percent # If the means of a continuous outcome variable in the same # two groups were 50 and 60 units and the standard deviations were 30 # and 35 units, then the power to detect a statistical significance # would be power.for.2means(mu1=50, mu2=60, sd1=30, sd2=35, n1=60, n2=60) # 39 percent. Note the graphic display