That's false. The only kind of events that cannot occur simultaneously are mutually exclusive events. Here are some true statements: Two events are said to be mutually exclusive if they cannot occur simultaneously. Two events are said to be dependent if the knowledge that one of them has occurred, is occurring, or will occur CHANGES the probability that the other one has occurred, is occurring, or will occur. If the occurrence of one INcreases the probability of the other, the events are said to be mutually supportive. If the occurrence of one DEcreases the probability of the other, the events are said to be mutually restrictive. Two or more events are said to be independent if the knowledge that one of them has occurred, is occurring, or will occur DOES NOT change the probability that the other one has occurred, is occurring, or will occur. Edwin