targetBeta {clinDR}R Documentation

Find a scaled Beta distribution matching specified probabilities

Description

Find the (a,b) parameters of a scaled Beta distribution with specified cummulative probabilities for two specified points from the distribution.

Usage

targetBeta(minval,pminV,pmaxV,maxval=1,aInit=1,bInit=1,upB=1)

Arguments

minval

The minimum value with a targetted cummulative probability

pminV

The targetted cummulative probability less than minval

pmaxV

The targetted cummulative probability less than maxval

maxval

The maximum value with a targetted cummulative probability

aInit

An initial guess for the first parameter of the scaled Beta distribution with the specified probabilities.

bInit

An initial guess for the second parameter of the scaled Beta distribution with the specified probabilities.

upB

The upper limit of the scaled Beta distribution. It is specified by the user.

Details

The Beta distribution with the targetted probabilities is found from starting values using the optim function.

Value

Returns the (a,b) parameters of the scaled beta distribution if one with the specified probabilities can be found. An error message is returned otherwise.

Author(s)

Neal Thomas

Examples

### set quartiles at .15 and 1.0 for a beta distribution on (0,3)
targetBeta(minval=.15,pminV=0.25,pmaxV=0.75,maxval=1.0,upB=3)

[Package clinDR version 2.3.5 Index]