Question

Use the contingency table to the right to determine the probability of events.

a. What is the probability of event​ A?

b. What is the probability of event A'​?

c. What is the probability of event A and​ B?

d. What is the probability of event A or​ B?

B   B`
A   40   70
A'   50   70

Answer 1

Answer:

Given,

	B	B'	Total
A	40	70	110
A'	50	70	120
Total	90	140	230

a) To determine the probability of event A

P(A) = 110 / 230

= 11 / 23

P(A) = 0.4783

b)

To determine the probability of event A'

P(A') = 120 / 230

= 12 / 23

P(A') = 0.5217

c)

To determine the probability of event A and B

P(A and B) = 40 / 230

= 4 / 23

P(A and B) = 0.1739

d)

To determine the probability of event A or B

P(A or B) = P(A) + P(B) - P(A and B)

= 110/230 + 90/230 - 40/230

= 0.4783 + 0.3913 - 0.1739

P(A or B) = 0.6957