1 Specify and Plan the Task Marks are awarded for thinking ahead. Make sure you explain: how you will ensure fair collection of data what data you need to collect what calculations you will need to do with the data what tables, charts or graphs you will be using with the data Strand 2 Collect Process and Represent Data Different types of calculation and charts score different marks. However, you do not score any marks for something that is not mentioned in either your plan or your conclusion. If you didn't plan to do something, that is OK, but you should explain in your con clu why you changed your mind Strand 3 Interpret and Discuss Results Once you have finished your coursework, you need to say what you think your project showed and maybe explain why you think it showed it. If you do not do this you score ZERO in this strand.

Conditional probabilities Let's look again at the previous example. The bag contains 4 red beads and 5 green beads. P (first bead is red) = P (first bead is green) = P (second bead is red, given that the first bead was red) = P (second bead is green, given that the first bead was red) = If the first bead is green, then there are 4 red and 4 green beads left in the bag. P (second bead is red, given that the first bead was green) = P (second bead is green, given that the first bead was green) = These are known as conditional probabilities and are best represented on a tree diagram. Remember The sum of the probabilities for any set of branches should always be 1.

From the tree diagram we can see that: P (both beads are red) = P (one bead of each colour) = P (both beads are green) = Easy? Try the following question yourself. The probability that Alex arrives home on time is 0. 7. If he does arrive home on time, the probability that his dinner is burnt is 0. 1. If he doesn't arrive home on time, the probability that his dinners burnt is 0.

8. Question 1 What is the probability that Alex arrives home on time and his dinner is not burnt? The Answer The probability that Alex arrives home on time and his dinner is not burnt is: 0. 7 x 0. 9 = 0.

63 Question 2 What is the probability that Alex's dinner is burnt?