Conditional Probability Worksheets

What Is Conditional Probability? 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 probability 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 the probability of 60%. The conditional probability will give you the outcome based on the relationship between these two events. That is the probability 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 probability 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 probability of getting a blue is 2 in 4.

  • Basic Lesson

    Introduces the application of conditional probability with playing cards. One card is drawn from a standard deck of cards. Find the probability of drawing a club or spade card?

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  • Intermediate Lesson

    This lesson focuses on conditional probability within random numbers. A number is selected from 1 to 15 at random. What is the probability of getting a number that is a multiple of 5?

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  • Independent Practice 1

    Students practice with 20 conditional probability problems. The answers can be found below. In a middle school of 200 students, 100 are seniors, 50 students take part in a play, and 30 students are seniors and are also taking part in play. What is the probability that a randomly chosen student is a senior and is taking part in play?

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  • Independent Practice 2

    Another 20 conditional probability problems. The answers can be found below. If the student selected is an 8th grade student, what is the probability that the student prefers Science or History?

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  • Homework Worksheet

    Reviews all skills in the unit. A great take home sheet. Also provides a practice problem.

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  • Skill Quiz

    10 problems that test Conditional Probability skills.

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  • Homework and Quiz Answer Key

    Answers for the homework and quiz.

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  • Answer Key

    Answers for the lesson and practice sheets.

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What Are The Odds?

A statistician was stopped because she had a bomb in her carry-on. The official said, "Why would you want to blow up a plane?" The woman replied, "I wasn't going to use it, but the odds of there being 2 bombs on one plane is 1 in 100,000."