pwr.anova.test {pwr} | R Documentation |
Compute power of test or determine parameters to obtain target power (same as power.anova.test except for the definition of the effect size).
pwr.anova.test(k = NULL, n = NULL, f = NULL, sig.level = 0.05, power = NULL)
k |
Number of groups |
n |
Number of observations (per group) |
f |
Effect size |
sig.level |
Significance level (Type I error probability) |
power |
Power of test (1 minus Type II error probability) |
Exactly one of the parameters 'k','n','f','power' and 'sig.level' must be passed as NULL, and that parameter is determined from the others. Notice that the last one has non-NULL default so NULL must be explicitly passed if you want to compute it.
Object of class 'power.htest', a list of the arguments (including the computed one) augmented with 'method' and 'note' elements.
'uniroot' is used to solve power equation for unknowns, so you may see errors from it, notably about inability to bracket the root when invalid arguments are given.
Stéphane Champely <champely@univ-lyon1.fr> but this is a mere copy of Cmaus Ekstrom work (power.anova.test)
J. Cohen (1988) Statistical power analysis for the behavioral scientist. Lawrence Erlbaum Associates, publishers.
power.anova.test
## Exercise 8.1 P. 357 from Cohen (1988) pwr.anova.test(f=0.28,k=4,n=20,sig.level=0.05) ## Exercise 8.10 p. 391 pwr.anova.test(f=0.28,k=4,power=0.80,sig.level=0.05)