| pwr.anova.test {pwr} | R Documentation |
Power calculations for balanced one-way analysis of variance tests
Description
Compute power of test or determine parameters to obtain target power (same as power.anova.test).
Usage
pwr.anova.test(k = NULL, n = NULL, f = NULL, sig.level = 0.05, power = NULL)
Arguments
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) |
Details
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.
Value
Object of class '"power.htest"', a list of the arguments (including the computed one) augmented with 'method' and 'note' elements.
Note
'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.
Author(s)
Stephane Champely <champely@univ-lyon1.fr> but this is a mere copy of Peter Dalgaard work (power.t.test)
References
Cohen, J. (1988). Statistical power analysis for the behavioral sciences (2nd ed.). Hillsdale,NJ: Lawrence Erlbaum.
See Also
power.anova.test
Examples
## 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)