In AliMUONTriggerChamberEfficiency:

In AliMUONTriggerChamberEfficiency:
When calculating efficiencies starting from the division of two histograms, a TGraphAsymmErrors is produced via TGraphAsymmErrors(const TH1* pass, const TH1* total, Option_t *option); following the guidelines of Page 27 of http://pdg.lbl.gov/2009/reviews/rpp2009-rev-statistics.pdf, the Clopper-Pearson 68% method is now used to determine errors. Explicitly specifying this option also prevents a segfault that occurs with the "tagged" v5-27-05-build1 of ROOT (rev.35249).
(F.Bossu, D.Berzano, D.Stocco, L.Bianchi)