1. An agreement breach prediction system, comprising: a correlation coefficient calculation unit that refers to the measured value information for analysis and learning relating to a measured value of a service item included in a service level agreement, and calculates, for each event that occurs in a target system of a service level agreement, a first correlation coefficient between a measured value at the time of occurrence of the event and a change value of the measured value in a period of time from occurrence of the event until a predefined time has elapsed; a filter unit that excludes, from targets of event information for analysis and learning relating to the event, the event for which the first correlation coefficient calculated by the correlation coefficient calculation unit is smaller than a predefined threshold value; a second correlation coefficient calculation unit that refers to the event information and calculates a second correlation coefficient between the respective events; a second filter unit that excludes, from the targets of the event information, the event for which the first correlation coefficient calculated by the correlation coefficient calculation unit is the smaller, from among two of the events corresponding to the second correlation coefficient, in a case where the second correlation coefficient calculated by the second correlation coefficient calculation unit is greater than a second predefined threshold value; a probability distribution calculation unit that, for each of events, calculates in a processor a probability distribution of a worst value among the measured values that have been measured during a period of time from a time at which the event occurs until a predefined time has elapsed therefrom, on the basis of the event information and of the measured value information, and that thereby generates beforehand a probability distribution to be referred to upon prediction of the occurrence of a service level agreement breach; a probability calculation unit that refers to the probability distribution calculated by the probability distribution calculation unit and to an agreement threshold value of the service item, and that calculates, for each of the events and an entire system, a probability that applies to a service level agreement breach and a probability that does not apply to the service level agreement breach, and that calculates, for each of the events, a probability that the event occurs when a service level agreement breach has not occurred within the predefined time and a probability that the event occurs when a service level agreement breach has occurred within the predefined time, on the basis of an expected value for each probability calculated; a probability density calculation unit that refers in a processor to the measured value information, and calculates a probability density of the measured value that applies to the service level agreement breach during a period of time from event occurrence until a predefined time has elapsed, and a probability density of the measured value that does not apply to the service level agreement breach during the period of time from the event occurrence until the predefined time has elapsed; and a breach occurrence probability calculation unit that, when the event occurs, calculates in a processor a probability that the agreement breach occurs within the predefined time after the occurrence of the event, by using the respective probabilities corresponding to the event and the respective probability densities corresponding to the measured values at a time of occurrence of the event.