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Computing power for one-way ANOVA in R

For type I error, alpha, regression degrees of freedom (= k-1 for k groups) and dfc covariates with a total sample size, ntot, a test to detect a R-squared of rsq has power, pow.

[COPY AND PASTE THE BELOW INTO R, ADJUST AS DESIRED]

alpha <- 0.05
dfreg <- 2
dfc <- 1
ntot <- 23
rsq <- 0.2

[COPY AND PASTE THE BELOW INTO R]

pow <- 1 - pf(abs(qf(1-alpha,dfreg,ntot-dfreg-dfc-1)),dfreg,ntot-dfreg-dfc-1,
ntot*rsq/(1-rsq))
print(pow) 

None: FAQ/powrsqR (last edited 2013-03-08 10:17:55 by localhost)