Probability
Overview
A weather forecaster who says '70% chance of rain' is not guessing: that number comes from counting how often rain followed similar conditions in the past. Probability turns uncertainty into a precise number between 0 and 1, and once events start combining, whether one after another or at the same time, a small set of rules tells you exactly how to combine their probabilities correctly.
This topic builds the probability scale, sample spaces and relative frequency, then covers the addition rule for mutually exclusive events, the product rule for independent events, tree diagrams for combined and conditional events, very simple conditional probability, and expected frequency.
Objectives
- Understand the language and basic concepts of probability including the probability scale, sample spaces, relative frequency, probabilities and complements
- Use the addition rule for two or more mutually exclusive events
- Use the product rule for two or more independent events
- Determine the probability of two or more independent events
- Use simple conditional probability for combined events using tree diagrams
- Find very simple conditional probability
- Understand and use the term expected frequency
Mind map
This topic is mapped out so you can see how the ideas connect.
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Flashcards
Quick recall practice on the facts this topic is tested on.
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Lesson Note
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Lesson Evaluation
Congratulations on completing the lesson on 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.
- P(rain) = 0.65. What is P(no rain)? A) 0.35 B) 0.65 C) 1.65 D) 0 Answer: A
- A fair die is rolled once. What is P(multiple of 2 or multiple of 3)? A) 1/6 B) 1/2 C) 2/3 D) 5/6 Answer: C
- Two fair coins are tossed. What is P(both land heads)? A) 1/2 B) 1/3 C) 1/4 D) 1/8 Answer: C
- A bag has 4 red and 6 blue counters. One is drawn and NOT replaced, then a second is drawn. What is P(second is red | first is red)? A) 4/10 B) 3/9 C) 4/9 D) 3/10 Answer: B
- A biased die has P(6) = 0.2. It is rolled 150 times. What is the expected number of sixes? A) 15 B) 20 C) 30 D) 75 Answer: C
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Recommended Books
Practice Mock Questions
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