beta.select {LearnBayes}

Selection of Beta Prior Given Knowledge of Two Quantiles

Description

Finds the shape parameters of a beta density that matches knowledge of two quantiles of the distribution.

Usage

beta.select(quantile1, quantile2)

Arguments

quantile1

list with components p, the value of the first probability, and x, the value of the first quantile

quantile2

list with components p, the value of the second probability, and x, the value of the second quantile

Value

vector of shape parameters of the matching beta distribution

Author(s)

Jim Albert

Examples

# person believes the median of the prior is 0.25 
# and the 90th percentile of the prior is 0.45
quantile1=list(p=.5,x=0.25)
quantile2=list(p=.9,x=0.45)
beta.select(quantile1,quantile2)