Читать книгу Applied Biostatistics for the Health Sciences - Richard J. Rossi - Страница 62

 Probabilities are always greater than or equal to 0. That is, P(A)≥0 for any event A.

 The probability of the sample space is 1. That is, P(S)=1, which means when the experiment is carried out it will result in one of the outcomes in S.

 The probability of every event is between 0 and 1. That is, 0≤P(A)≤1 for every event A.

 When two events have no outcomes in common, then the probability that at least one of the two events occurs is the sum of their probabilities. That is,when A and B have no outcomes in common.

Events that have no outcomes in common are called disjoint events or mutually exclusive events. If A and B are disjoint events, then the probability of the event “A and B” is 0. That is, it is impossible for the events to occur simultaneously.