Conditional Probability
Overview
Sometimes one event changes the chance of another. If you draw a counter from a bag and keep it, the next draw is from a smaller bag, so the probabilities shift. Conditional probability is the mathematics of these knock-on effects: the probability of one event given that another has already happened.
In this Extended topic you will work with conditional probability using tables, Venn diagrams and tree diagrams. The classic setting is drawing objects without replacement, where each draw alters what remains. Once you see how the branch probabilities change after the first event, problems that look hard become a tidy multiplication along a path.
Objectives
- Calculate conditional probability using Venn diagrams, tree diagrams and tables.
Lesson Note
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Lesson Evaluation
Congratulations on completing the lesson on Conditional Probability. Now that youve explored the key concepts and ideas, its time to put your knowledge to the test. This section offers a variety of practice questions designed to reinforce your understanding and help you gauge your grasp of the material.
You will encounter a mix of question types, including multiple-choice questions, short answer questions, and essay questions. Each question is thoughtfully crafted to assess different aspects of your knowledge and critical thinking skills.
Use this evaluation section as an opportunity to reinforce your understanding of the topic and to identify any areas where you may need additional study. Don't be discouraged by any challenges you encounter; instead, view them as opportunities for growth and improvement.
- A bag has 5 red and 3 blue counters. Two are drawn without replacement. What is P(both red)? A. 25/64 B. 20/56 C. 5/8 D. 4/7 Answer: B
- After drawing one red from a bag of 5 red and 3 blue (kept out), what is the probability the next is red? A. 5/8 B. 5/7 C. 4/7 D. 4/8 Answer: C
- Of 18 French students, 12 also study Spanish. A French student is chosen. What is P(studies Spanish)? A. 1/3 B. 2/5 C. 2/3 D. 12/30 Answer: C
- Which rule gives the probability of A and B in general? A. P(A) + P(B) B. P(A) x P(B given A) C. P(A) - P(B) D. P(A) / P(B) Answer: B
- A bag has 4 white and 2 black balls. Two are drawn without replacement. What is P(both white)? A. 4/9 B. 2/5 C. 1/3 D. 12/30 Answer: B
Available on the Green Bridge App
Download the Green Bridge CBT app on your phone or computer to access full lesson notes, practice questions, and more.
Available on the Green Bridge App
Download the Green Bridge CBT app on your phone or computer to access full lesson notes, practice questions, and more.
Recommended Books
Practice Mock Questions
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