| 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 |
pmaxV |
The targetted cummulative probability less than |
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)