WJEC Maths for A2 – Applied

9 Introduction You were introduced to probability in the AS course but before starting this topic you should take a look back at the AS Applied book at Topic 3 Probability on pages 55 to 68. In the AS, you looked at the probability of independent events, which meant that the probability of a first event occurring did not influence the probability of a second event occurring. Such events are called independent events. In many cases the probability of the second event occurring is dependent on whether or not the first event occurs and such events are called dependent events and the probability of the events occurring is called conditional probability. This topic looks at the probability of dependent events and the various methods of finding their probability. This topic covers the following: 1.1 Using tree diagrams for conditional probability 1.2 The conditional probability formula 1.3 Use of Venn diagrams for conditional probability 1.4 Use of two-way tables for conditional probability 1.5 Modelling with probability