Question

Suppose the probability of an event occurring is P(A) , and the probability of the event not occurring is P(A’). If P(A)=s and P(A’) = t which of the following equations must be true ? A. t= 1-s

B. s= 1+t C. s= t-1 D. t= s+1!

Answer 1

The correct answer is A) t = 1-s.

The probability of the complement of an event is the probability of the event subtracted from 1; in other words
P(A') = 1 - P(A)

Since P(A') = t and P(A) = s,
t = 1-s