Compute power of tests or determine parameters to obtain target power (similar to as power.t.test).
pwr.t2n.test(n1 = NULL, n2= NULL, d = NULL, sig.level = 0.05, power = NULL,
alternative = c("two.sided",
"less","greater"))Number of observations in the first sample
Number of observations in the second sample
Effect size
Significance level (Type I error probability)
Power of test (1 minus Type II error probability)
a character string specifying the alternative hypothesis, must be one of "two.sided" (default), "greater" or "less"
Object of class '"power.htest"', a list of the arguments (including the computed one) augmented with 'method' and 'note' elements.
Exactly one of the parameters 'd','n1','n2','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.
Cohen, J. (1988). Statistical power analysis for the behavioral sciences (2nd ed.). Hillsdale,NJ: Lawrence Erlbaum.
# NOT RUN {
## Exercise 2.3 p. 437 from Cohen (1988)
pwr.t2n.test(d=0.6,n1=90,n2=60,alternative="greater")
# }
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