Let E1, E2, E3, …, En be n mutually exclusive events associated with a random experiment. If A is an event which occurs as a result of the events (cases) E1, E2, E3, …, En then
P(
Ei
A
) = Probability of occurrence of event A as a result of a particular cause (event) Ei
P(Ei).P(A)
n
∑
i=1
P(Ei).P(
A
Ei
)
i = 1,2,..., n
