Target 4-A, Target 4-B, Target 4-C, Target 4-D

Target 4-A

  

Understand the language of probability.

  • Use “event”, “trial”, and “complement” correctly.
  • Use proper notation.
  • Interpret what the notation means.
  • Find the probability of a simple event.
  • Find the probability of the complement of an event.

 

 

Sample Questions

Joey has a bag containing 3 blue, 5 green, and 2 red marbles. He randomly picks a marble from the bag and then replaces the marble back into the bag.

  1. What is the probability that he chooses a blue marble?
  2. Explain the notation P(green) means.
  3. What is the probability of Joey not picking a red marble?. What probability word describes this type of situation?
  4. Explain the difference between "trial" and "event" for this situation.

Sample Response
  1. The probability that he chooses a blue marble is 3/10.
  2. P(green) means the probability he picks a green marble.
  3. The probability of Joey not picking a red marble is 1 − 2/10 = 8/10. This is a "complement" situation. The probability of getting a red marble is 2/10. The probability of the complement is then 1 − 2/10.
  4. A "trial" is Joey picking a marble out of the bag and replacing it. An "event" is what we are wondering about, namely what happened. For example, we might want to know the probability of Joey picking a red marble. He might or might not get a red one. Each time he picks a marble is a "trial". The "event" would be him picking a red one.