independent
if knowing whether one event occurs does not effect the probability that the other event occurs
P(A and B)
P(A) x P(B)
if mutually exclusive P (A or B)
P(A) + P(B)
P(A or B)
P(A) + P(B) - P(A or B)
P(at least one)
= 1 - P(none)
dependent
one occurrence of a certain event effects the occurrence of a different event
mutually exclusive (disjoint)
do not have any common outcomes
intersection
two events A and B consists of the outcomes in both A and B
union
two events A and B consists of the outcomes that are in A or B. In probability, "A or B" denotes that A occurs or B occurs or both occur.
Venn diagram
a diagram that uses circles to represent mathematical or logical sets pictorially inside a rectangle