# NOT RUN {
# Suppose the population error variance of some three-group ANOVA model
# is believed to be 40, and the population correlation coefficient
# of the response and the covariate is 0.22. The researcher is
# interested in the difference between the mean of group 1 and
# the average of means of group 2 and 3. To plan the sample size so
# that, with 90 percent certainty, the obtained 95 percent full
# confidence interval width is no wider than 3:
ss.aipe.c.ancova(error.var.anova=40, rho=.22,
c.weights=c(1, -0.5, -0.5), width=3, assurance=.90)
# }
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