Conditional Probability – Call it in the Air!

The conditional probability of an event B, in relation to event A, is the probability that event B will occur given the knowledge that an event A has already occurred.

Listen, there are VERY FEW times in your Algebra 2 classes that you get to just HAVE FUN teaching a lesson! Don’t let this opportunity pass you by. I always spend more time on this lesson than I should. Why? Because it is a point in the course where you can re-ignite your students interest in your class.

There are so many activities you can do to help you teach this lesson and get your students truly involved I could never list them all. But here are my top 5!

Split your class into groups, give them a bowl of M&M’s or Skittles, give them a list of questions on finding different probabilities for drawing the right color. Watch them enjoy. If you want to make it more exciting then have them also do the activity with a blind fold on and ACTUALLY pick random candy out of the bowl.

Another small group activity. Same concept but more realistic. Deal out hands of cards to each member of the group. Have them figure out what the probability of the next card will be.

Using Dice to teach conditional probability can be both good and bad. Good because you can compare it to the other types of probability that are great with dice because of the fact that you can’t remove a number from dice if it is rolled. Bad because you can’t remove a number from the dice when it is rolled. Replacement is not needed in conditional probability so you will have to get them to think rather than do if you decide to use dice. They can’t remove numbers but they can pretend it is a loaded dice or that they can’t roll the same number twice.

This was created by MIT and is a great real world application of conditional probability. The question at hand seems really complex and to think that a test can be 96% accurate or more is a lot for the students to wrap their heads around. However, this lesson will get them to understand how the accuracy of tests for cancer can be calculated by Algebra 2 students and not necessarily MIT students!

Obviously another one where you can’t replace the face on the coin but this way of teaching probability is good for classes that are not as math savvy because of the coin having two options.