Relative And Expected Frequencies
Overview
Not every probability can be worked out by counting equally likely outcomes. What is the chance a drawing pin lands point up, or that a particular footballer scores a penalty? For these we have to experiment, and that is where relative frequency comes in: we run trials, record what happens, and use the results to estimate the probability.
In this lesson you will learn how relative frequency estimates a probability from real data, and why more trials give a better estimate. You will then turn the idea around: given a probability and a number of trials, you will predict how often an event should happen using expected frequency. Together these two ideas connect probability to the real world of experiments and surveys.
Objectives
- Understand relative frequency as an estimate of probability.
- Calculate expected frequencies.
Lesson Note
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Lesson Evaluation
Congratulations on completing the lesson on Relative And Expected Frequencies. 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 spinner is spun 200 times and lands on red 50 times. Estimate the probability of red. A. 0.1 B. 0.25 C. 0.4 D. 0.5 Answer: B
- The probability of an event is 0.2. In 50 trials, what is the expected frequency? A. 5 B. 10 C. 20 D. 25 Answer: B
- A fair die is rolled 120 times. How many times would you expect to roll a 4? A. 6 B. 12 C. 20 D. 24 Answer: C
- Which gives the most reliable estimate of a probability from an experiment? A. 5 trials B. 20 trials C. 100 trials D. 1000 trials Answer: D
- A bag of seeds has a germination probability of 0.9. Out of 300 seeds, how many are expected to germinate? A. 27 B. 90 C. 210 D. 270 Answer: D
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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