Question

what does the complement rule state?

a. ( p(a) = p(a) x + p(b) )
b. ( p(a) = 1 - p(\text{not } a) )
c. ( p(a) = p(a) cdot p(b) )
d. ( p(a) = p(a) - p(b) )

Explanation:

The complement rule in probability relates the probability of an event occurring to the probability of it not occurring. The total probability of all possible outcomes is 1, so the probability of event A is equal to 1 minus the probability that A does not happen.

Answer:

b. $P(A) = 1 - P(\text{not }A)$