Nothing
"pwr.r.test" <-
function (n = NULL, r = NULL, sig.level = 0.05, power = NULL,
alternative = c("two.sided", "less","greater"))
{
if (sum(sapply(list(n, r, power, sig.level), is.null)) !=
1)
stop("exactly one of n, r, power, and sig.level must be NULL")
if (!is.null(r) && is.character(r))
r <- cohen.ES(test="r",size=r)$effect.size
if (!is.null(sig.level) && !is.numeric(sig.level) || any(0 >
sig.level | sig.level > 1))
stop(sQuote("sig.level"), " must be numeric in [0, 1]")
if (!is.null(power) && !is.numeric(power) || any(0 > power |
power > 1))
stop(sQuote("power"), " must be numeric in [0, 1]")
if (!is.null(n) && any(n < 4))
stop("number of observations must be at least 4")
alternative <- match.arg(alternative)
tside <- switch(alternative, less = 1, two.sided = 2,greater=3)
if (tside == 2 && !is.null(r))
r <- abs(r)
if (tside == 3) {
p.body <- quote({
ttt <- qt(sig.level, df = n - 2, lower = FALSE)
rc <- sqrt(ttt^2/(ttt^2 + n - 2))
zr <- atanh(r) + r/(2 * (n - 1))
zrc <- atanh(rc) # + rc/(2 * (n - 1))
pnorm((zr - zrc) * sqrt(n - 3))
})
}
if (tside == 1) {
p.body <- quote({
r<--r
ttt <- qt(sig.level, df = n - 2, lower = FALSE)
rc <- sqrt(ttt^2/(ttt^2 + n - 2))
zr <- atanh(r) + r/(2 * (n - 1))
zrc <- atanh(rc) # + rc/(2 * (n - 1))
pnorm((zr - zrc) * sqrt(n - 3))
})
}
if (tside == 2) {
p.body <- quote({
ttt <- qt(sig.level/2, df = n - 2, lower = FALSE)
rc <- sqrt(ttt^2/(ttt^2 + n - 2))
zr <- atanh(r) + r/(2 * (n - 1))
zrc <- atanh(rc) # + rc/(2 * (n - 1))
pnorm((zr - zrc) * sqrt(n - 3)) + pnorm((-zr - zrc) *
sqrt(n - 3))
})
}
if (is.null(power))
power <- eval(p.body)
else if (is.null(n))
n <- uniroot(function(n) eval(p.body) - power, c(4 +
1e-10, 1e+09))$root
else if (is.null(r)){
if(tside==2)
r <- uniroot(function(r) eval(p.body) - power,
c(1e-10,1 - 1e-10))$root
else
r <- uniroot(function(r) eval(p.body) - power,
c(-1+1e-10, 1 - 1e-10))$root
}
else if (is.null(sig.level))
sig.level <- uniroot(function(sig.level) eval(p.body) - power,
c(1e-10, 1 - 1e-10))$root
else stop("internal error")
METHOD <- "approximate correlation power calculation (arctangh transformation)"
structure(list(n = n, r = r, sig.level = sig.level, power = power,
alternative = alternative, method = METHOD), class = "power.htest")
}
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