In this unit, students will extend their work with ratios and proportional reasoning to consider the probability of a random event like spinning a spinner, rolling a die, or drawing randomly from a collection. To find probabilities, they will determine the number of possible outcomes for an event, and will represent probabilities as ratios using both experimental and theoretical models.
Students will interpret a probability as the proportion of the time that an event occurs when a chance experiment is repeated many times, as they develop an understanding that a probability is a number between 0 and 1 that represents the likelihood that an event will occur.
They will use probabilities and proportional reasoning to estimate and predict quantities based on the number of observations of an event. As they investigate chance processes, they will observe that, while probabilities can allow them to predict likelihoods, actual results may vary from their predictions.
Key Concepts:
 We can generate hypotheses about the likelihood of an event by counting the number of times the event occurs and comparing it to the total number of possible outcomes or observations.
 The probability of a simple event is the same as the ratio of the number of favorable outcomes to the number of possible outcomes. This may be expressed as a decimal between 0 and 1, with 0 being impossible, and 1 being certain to occur.
 The actual frequency of an event occurring is not expected to be exactly the same as the predicted frequency in a probability model. The accuracy of the prediction improves as the number of observations increases.
Prior Knowledge Needed:
 Understand ratio concepts and use ratio reasoning to solve problems; (Grade 6, Unit 1; 6.RP.A.1)
 Analyze proportional relationships and use them to solve realworld and mathematical problems; (Grade 7, Units 1, 2 and 3; 7.RP.A.3)
Units on the Horizon:
 Probability of compound events (Grade 7, Unit 9)
 Sampling, inferences, and comparing populations (Grade 7, Unit 10)
Lessons

Lesson objective: Understand that we can generate hypotheses about the likelihood of an event by counting possible outcomes and favorable outcomes. Students bring prior knowledge of parttopart and parttowhole comparisons from 6th Grade (6.RP.A.1). T...

Lesson objective: Calculate the experimental probability based on data collected from an experiment on a spinner. This lesson helps to build procedural skill with calculating experimental probabilities. Fractions are used here because they clearly repre...

Lesson objective: Apply understanding of collecting and organizing data to write experimental probabilities with a nonuniform event, dropping a plastic dinosaur to see how it lands. This lesson provides an opportunity for students to apply their knowle...

Lesson objective: Understand that the probability of a random event can be written as the ratio of favorable outcomes to all possible outcomes. This can be expressed as a decimal or percent between 0 and 1. Students bring prior knowledge of ratios from ...

Lesson objective: Calculate probabilities of complementary events and events that use "or." This lesson helps to build procedural skill with finding probabilities. Ratios and percents are used because probabilities can be represented, added, and subtrac...

Lesson objective: Predict number of times an outcome will occur using theoretical probabilities. This lesson helps build procedural skill using theoretical probabilities to make predictions. Tables and proportions are used here because proportional reas...

Lesson objective: Apply using theoretical probabilities to make predictions about quantities. This lesson provides an opportunity for students to apply their knowledge and understanding of theoretical probabilities to a spinner game choice situation. St...

Lesson objective: Understand that the actual frequency of an event occurring is not expected to be exactly the same as the predicted frequency in a probability model. Students bring prior knowledge of experimental and theoretical probability from 7.SP.C...

Lesson objective: Estimate quantities in realworld scenarios using experimental probabilities written as percents. This lesson helps to build procedural skill with calculating experimental probabilities as percents. Percents are used here because they ...

Lesson objective: Apply experimental probabilities to estimate the quantity of each coin, and the total amount of money, in a mystery bag of change. This lesson provides an opportunity for students to apply their knowledge and understanding of experimen...