Discussion Time Chapter 18 Probability I Page 379

Discussion Time Chapter 18 : Probability I Page: 379

Question posed: 1. Flip a coin 50 times and record your results in a table. 2. What is your sample space? 3. Work out P(head) and P(tail). 4. Take results from five other pairs and work out P(head) and P(tail) for 300 flips. (Make sure that the coins used by the other pairs are the same shape and size. ) Now discuss the following: When we do an experiment, are the results always the same? Which probabilities are more reliable, your results from 50 flips or the group’s results as a whole? Why does the number of times we do the experiment affect the accuracy of the experimental probabilities we get? Chapter 18: Probability I page 379 2

Suggested solution: 1. Flip a coin 50 times and record your results in a table. Number of Heads Number of Tails 2. What is your sample space? Sample space = {Head, Tail} 3. Work out P(head) and P(tail). P(Head) = P(Tail) = Chapter 18: Probability I page 379 3

4. Take results from five other pairs and work out P(head) and P(tail) for 300 flips. Number of Heads Number of Tails Own group Group 1 Group 2 Group 3 Group 4 Group 5 Total P(Head) = P(Tail) = Chapter 18: Probability I page 379 4

Discussion: When we do an experiment, are the results always the same? No. Experiments are subject to variation so the results will not always be the same. Which probabilities are more reliable, your results from 50 flips or the group’s results as a whole? Why? The group’s results as a whole should be more reliable. This is because the group as a whole represents the results of 300 flips whereas your results are for 50 flips. Why does the number of times we do the experiment affect the accuracy of the experimental probabilities we get? In general the more times you flip the coin the closer the results will get to theoretical probability. Chapter 18: Probability I page 379 5