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.

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]