An act’s expected utility is a probability-weighted average of its possible outcomes’ utilities. Possible states of the world that are mutually exclusive and jointly exhaustive, and so form a partition, generate an act’s possible outcomes. An act-state pair specifies an outcome. In the example, the act of studying and the state of passing form an outcome comprising the effort of studying and the benefit of passing. The expected utility of studying is the probability of passing if one studies times the utility of studying and passing plus the probability of not passing if one studies times the utility of studying and not passing. In compact notation,