Power analysis functions along the lines of Cohen (1988).

- pwr.r.test: Power calculations for correlation test
- pwr.t.test: Power calculations for t-tests of means (one sample, two samples and paired samples)
- ES.w2: Effect size calculation in the chi-squared testfor association
- pwr.anova.test: Power calculations for balanced one-way analysis of variance tests
- pwr.f2.test: Power calculations for the general linear model
- pwr.norm.test: Power calculations for the mean of a normal distribution (known variance)
- ES.w1: Effect size calculation in the chi-squared test for goodness of fit
- pwr.2p2n.test: Power calculation for two proportions (different sample sizes)
- pwr.p.test: Power calculations for proportion tests (one sample)
- ES.h: Effect size calculation for proportions
- cohen.ES: Conventional effects size
- pwr.chisq.test: power calculations for chi-squared tests
- pwr.t2n.test: Power calculations for two samples (different sizes) t-tests of means
- pwr.2p.test: Power calculation for two proportions (same sample sizes)
- plot.power.htest: Plot diagram of sample size vs. test power