Power {epicalc} | R Documentation |
Calculation for power given the results
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 sample |
n1, n2 |
sample sizes of the two sample |
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 results
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 found at .8 and .6 but 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 an continuous outcome variable in the same # two groups were 50 and 60 units and the sd's were 30 and 35 units, # then the power to detect 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