In these worksheets, students will learn to determine the conditional probability of a statement.

#### The probability that is defined as the possibility for the likelihood of the following event based on the result of the previous event. Conditional probability is found out by multiplying the probability of the previous into the expectation of the succeeding event. For example: You have event A that represents that there is a 20% chance of rain today. You have event B that represents that you have to go outside and has a probability of 60%. The conditional probability will give you the outcome based on the relationship between these two events. That is the chance value that represents both, you need to go outside, and it is raining. Independent events are events that are not affected by one another. For example, tossing a coin. In a coin toss, each toss is an independent event and an isolated outcome. Events can also be dependent. That is, both the events are affected by each other. The next event is affected by the possibility of the previous event. For example, 2 blue and 3 red balls are in the bag. The probability of getting a blue ball is 2 in 5. But if we got a red ball before, then the likelihood of getting a blue is 2 in 4. Conditional probability is the likelihood of event A occurring, given that event B has occurred.

In these worksheets, the conditional probability problems are presented as word problems. Students will read the word problems and determine the prospective outcome that is being requested. Students may require blank paper to use to do their work. This set of worksheets contains step-by-step solutions to sample problems, both simple and more complex problems, a review, and a quiz. Worksheets are also provided that students can use for independent practice. When finished with this set of worksheets, students will be able to determine the known probability of a statement. These worksheets explain how to determine conditional probability. These word problems directly relate to every day work students will need to cover and handle with great ease.

# Conditional Probability Worksheets

## Lesson

What is the probability of choosing E or T from letters of word HELICOPTER? We walk you through how to solve these types of problems.

## Practice Worksheet

Students will determine the conditional probability of each statement. Example problem: In New York State, 48% of all teenagers own a skateboard and 39% of all teenagers own a skateboard and roller blades. What is the probability that a teenager owns roller blades given that the teenager owns a skateboard?

## More Practice

More work for you on conditional probability. Here is an example: A new bag of golf tees contains 10 red tees, 10 orange tees, 10 green tees and 10 blue tees. You empty the tees into your golf bag. What is the probability of picking two tees of the same color in a row for you and your partner?

## Review and Practice

The concept of how to multiply determine conditional probability is reviewed. Another sample problem: A machine produces parts that are either good (90%), slightly defective (2%), or obviously defective (8%). Produced parts get passed through an automatic inspection machine, which is able to detect any part that is obviously defective and discard it. What is the quality of the parts that make it through the inspection machine and get shipped?

## Content Quiz

Students will demonstrate their proficiency in determining the conditional probability of each statement. Ten problems are provided.

## Skills Check

This is a really fun worksheet that can be used to solve three problems as a class. Example exercise: Consider the game in which there are three doors (numbered 1, 2, 3), one of which has a car behind it and two of which are empty. Max initially selects Door 1, then, before it is opened, Monty Hall tells you that Door 3 is empty. Max is then given the option to switch your selection from Door 1 to the unopened Door 2. What is the probability that Max will win the car if you switch your door selection to Door 2?