twCoefLogitnormCi: twCoefLogitnormCi

In bgctw/logitnorm: Functions for the Logitnormal Distribution

twCoefLogitnormCi

Description

Calculates mu and sigma of the logitnormal distribution from lower and upper quantile, i.e. confidence interval.

Usage

twCoefLogitnormCi(lower, upper, perc = 0.975, 
    sigmaFac = qnorm(perc), isTransScale = FALSE)

Arguments

lower	value at the lower quantile, i.e. practical minimum
upper	value at the upper quantile, i.e. practical maximum
perc	numeric vector: the probability for which the quantile was specified
sigmaFac	sigmaFac = 2 is 95% sigmaFac = 2.6 is 99% interval
isTransScale	if true lower and upper are already on logit scale

Value

named numeric vector: mu and sigma parameter of the logitnormal distribution.

Author(s)

Thomas Wutzler

See Also

logitnorm

Examples

mu = 2
sd = c(1,0.8)
p = 0.99
lower <- l <- qlogitnorm(1 - p, mu, sd )		# p-confidence interval
upper <- u <- qlogitnorm(p, mu, sd )		# p-confidence interval
cf <- twCoefLogitnormCi(lower,upper, perc = p)	
all.equal( cf[,"mu"] , c(mu,mu) )
all.equal( cf[,"sigma"] , sd )

bgctw/logitnorm documentation built on Feb. 2, 2024, 12:57 a.m.