©G Dear 2009 – Not to be sold/Free to use Relative Frequency General Mathematics Preliminary Relative Frequency Stage 6 - Year 11 Press Ctrl-A ©G Dear 2009 – Not to be sold/Free to use

Complementary Events (1/3) Definition The Complementary Event is the event that describes all other possible events. Example: E = {winning a race} Complement of E = {NOT winning a race} Complement of E = {loosing a race} Wrong

Complementary Events (2/3) The Sum of the Probabilities of an Event and its Complement add to ‘1’. Example: For a dice 2 6 1 3 P(>4) = = 4 6 2 3 P( Complement >4) = P(≤4) = = 1 3 2 3 P(>4) + P( Complement >4) = + = 1

Complementary Events (3/3) To find the Probability of an Event, subtract the probability of its Complement from ‘1’. Example: For a standard pack of cards P(Spot Card) = 1 - P( Not Spot Card) 12 52 - = 1 10 13 =