Get prior parameters from Beta distribution

Compute the shape parameters from a Beta distribution for \(\delta\) based on some prior belief.

getPrior_delta(lower, upper, p = 0.7, mode, conc, plot = TRUE)

Arguments

lower,upper,p	numeric. Prior belief about the reduction. There is p probability that the reduction is between lower and upper. Not used if mode and conc are supplied.
mode,conc	numeric. Prior belief about the reduction. The mode and concentration parameters of a beta distribution. Higher concentration indicates smaller variance. Not used if lower and upper thresholds are supplied.
plot	logical. If TRUE, the prior distribution is plotted after parameters are found.

Value

Returns Beta prior parameters for \(\delta\) and the printed argument to use in a fecr_stan() or a fec_stan() function call.

Details

The multiroot function from rootSolve package is used to compute the parameters.

Examples

# there is 80% probability that the reduction is between 60% and 90%
getPrior_delta(lower = 0.6, upper = 0.9, p = 0.8)
#> [1] "deltaPrior = list(priorDist = 'beta', hyperpars = c(9.488, 2.998))"