I'm interested in the question of defining a reliability parameter of a model of the probability of an event. Say you're tossing a fair coin, with a 50% chance of heads. Your model tells you it's 40% of the coin showing heads. How reliable is your model? Say you're tossing coins A1,A2,... each with probability P1,P2,... of showing heads. Your model tells you it's T1,T2,... How reliable is your model? Is there a concept in statistics concerning the reliability of events? I'm trying to figure out a method of determining the reliability of a model that has constantly changing probabilities, but I'd first like to know the basic concept to develop a method of calculating its reliability.