// @(#)root/roostats:$Id: HypoTestResult.h 26434 2008-11-24 21:29:32Z moneta $
// Author: Kyle Cranmer, Lorenzo Moneta, Gregory Schott, Wouter Verkerke
/*************************************************************************
 * Copyright (C) 1995-2008, Rene Brun and Fons Rademakers.               *
 * All rights reserved.                                                  *
 *                                                                       *
 * For the licensing terms see $ROOTSYS/LICENSE.                         *
 * For the list of contributors see $ROOTSYS/README/CREDITS.             *
 *************************************************************************/

#ifndef ROOSTATS_HypoTestResult
#define ROOSTATS_HypoTestResult

#ifndef ROOT_TNamed
#include "TNamed.h"
#endif

#ifndef ROOSTATS_RooStatsUtils
#include "RooStats/RooStatsUtils.h"
#endif

namespace RooStats {

   class HypoTestResult : public TNamed {

   public:
      HypoTestResult();
      HypoTestResult(const char* name, Double_t nullp, Double_t altp);
      HypoTestResult(const char* name, const char* title, Double_t nullp, Double_t altp);
      virtual ~HypoTestResult();

      // Return p-value for null hypothesis
      virtual Double_t NullPValue() const {return fNullPValue;}

      // Return p-value for alternate hypothesis
      virtual Double_t AlternatePValue() const {return fAlternatePValue;}

      // Convert  NullPValue into a "confidence level"
      virtual Double_t CLb() const {return 1.-NullPValue();}

      // Convert  AlternatePValue into a "confidence level"
      virtual Double_t CLsplusb() const {return AlternatePValue();}

      // CLs is simply CLs+b/CLb (not a method, but a quantity)
      virtual Double_t CLs() const {
       double thisCLb = CLb();
        if (thisCLb==0) {
          std::cout << "Error: Cannot compute CLs because CLb = 0. Returning CLs = -1\n";
          return -1;
        }
        double thisCLsb = CLsplusb();
        return thisCLsb/thisCLb;
      }

      // familiar name for the Null p-value in terms of 1-sided Gaussian significance
      virtual Double_t Significance() const {return RooStats::PValueToSignificance( NullPValue() ); }

   protected:

      mutable Double_t fNullPValue; // p-value for the null hypothesis (small number means disfavored)
      mutable Double_t fAlternatePValue; // p-value for the alternate hypothesis (small number means disfavored)

      ClassDef(HypoTestResult,1)  // Base class to represent results of a hypothesis test

   };
}


#endif