Use of InverseCDF from RooStats/SamplingDistribution.h

Hello out there,

I’d like to use the Inverse cumulative distribution function provided by RooStats. In doing so I just call the Function as part of a Double_t expression.

Minimal Example:

#include "RooStats/SamplingDistribution.h"
using namespace RooStats;

void func(){
Double_t mu,alpha=0.05,beta=0.16;



However Root only states that InverseCDF is not defined in current scope.
Am I using the wrong header files?
Does anybody have a solution to this problem because I didn’t found anything in the documentation


I am not sure of what you want to do. SamplingDistribution::InverseCDF( double p) returns the inverse of the empirical cumulative distribution obtained with a vector of data. It is equivalent (although implement differently) to TMath::Quantile (see … :Quantiles ).
Actually TMath::Quantiles provides in addition different options to interpolate the different points.

Example to use:
To get the median of a SamplingDistribution you can do:

SamplingDistribution * s = ...
double median = s->InverseCDF(0.5);


double p[1] = 0.5; double q[1];
TMath::Quantiles(s->GetSize(), 1, &s->GetSamplingDistribution()[0], q, p, false);