Independent Events The probability of one event happening isn’t influenced by the outcome of another.
In mathematical terms
## AB events P(AnnB)=P(A)*P(B)##
This reads: Probability of A and B happening is equal to the probability of A happening multiplied by the probability of B happening
An equivalent definition
##P(A|B) = P(A)##
This reads: The probability of A given B happened is equal the probability of A
Example:
Event A: Rolling a number larger than four on a die in the first roll Event B: Rolling a 6 on a die on the second roll. These events are independent because one roll of a dice doesn’t influence the outcome of another dice roll.
Dependent Events Is the oposite.If the outcome of one event influences the probability of the other they aren’t independent
##P(A|B) != P(A)##
Example:
Event A: Rolling a number larger than four on a die Event B: Rolling a 6 on a die on the same roll. These events are dependent because as we are in the same dice roll the occurrence of event B changes the probability of event A actually it makes it 1.
Observation:
Pay attention that if you are dealing with more than 2 event for them to be mutually independent every possible combination of them must be. For example if we are dealing with 3 events independence means that:
##P(AnnBnnC)=P(A)*P(B)*P(C)##
## and P(AnnB) = P(A)*P(B) P(BnnC)=P(B)*P(C) P(CnnB)=P(C)*P(B)##