SOME SUPER COIN TOSSERS

CHAP 6.2 B PROBABILITY MODELS

CALCULATING PROBABILITY

PROBABILITY RULES

EXAMPLE Solution: a. The probability of each outcome is a number between 0 and 1, and the probabilities of all the possible outcomes add to 1, so this is a legitimate probability model. b. Solve using complement or Addition rule 0.43 or 43%

PROBABILITY RULES

EXAMPLE On January 28, 1986, Space Shuttle Challenger exploded on takeoff. All seven crew members were killed. Following the disaster, scientists and statisticians helped analyze what went wrong. They determined that the failure of O-ring joints in the shuttle’s booster rockets was to blame. Under the cold conditions that day, experts estimated that the probability that an individual O-ring joint would function properly was But there were six of these O-ring joints, and all six had to function properly for the shuttle to launch safely. Assuming that O-ring joints succeed or fail independently, find the probability that the shuttle would launch safely under similar conditions. Solution: 0.87 or 87%

AP EXAM TIP Many probability problems involve simple computations that you can do on your calculator. It may be tempting to just write down your final answer without showing the supporting work. DON’T DO IT! A “naked answer,” even if it’s correct, will usually earn you no credit on a free response question.

VIENN DIAGRAMS

In Class: 55, 57, 58 Suggested HW: 38, 40, 45-48, 51