A B C D

Notes for Session 8, Part C

 Note 7 The purpose of Part C is to investigate the idea and use of the binomial probability model. Part C analyzes the question of how many times you will get heads when you toss a coin a given number of times. The outcome of a coin toss is a random event, so any answer to the question requires the use of probability. Tree diagrams are used to analyze the coin toss problem. A tree diagram is a useful tool for analysis and also an effective pedagogical device.

 Note 8 The tree diagram for two tosses of a fair coin helps to relate the four possible outcomes to the number of heads for each outcome: The key idea is to determine how many outcomes (paths through the tree) contain zero heads, one head, or two heads, respectively. Some people have great difficulty with the notion that some values occur more often than others. They think that if there are three possible values (zero, one, and two), then each must be equally likely. The tree diagram may clarify the different frequencies of occurrence for different possible outcomes.