Addition rule

Question 1

Addition rule - 1

Answer 1

• P(A u B) = P(A) + P(B) - P(A n B)

Question 2

Addition rule disjoint events - 1

Answer 2

• P(A u B) = P(A) + P(B)

Question 3

Disjoint events - 3

Answer 3

• Two events are disjoint if they cannot happen at the same time.
• A n B = ø
• For m disjoint events the probability of the events happening is equal to the sum of the probability of each individual event.

Question 4

Complement (and complement rule) - 2

Answer 4

• The complement of A (A bar or Ac) is the set of outcomes which is not in A
• P(A bar) = 1 - P(A)