CCSS.Math.Content.7.SP.C.7a
The standard
Develop a uniform probability model by assigning equal probability to all outcomes, and use the model to determine probabilities of events.
Common Core State Standards for Mathematics
What this standard means
Students need to recognize when outcomes are equally likely, list the full sample space, and assign each outcome the same probability. Then they use that model to find the probability of an event by counting favorable outcomes over total outcomes.
Mastery looks like clean lists, correct fractions, and clear reasoning about why the model is fair. Students often get stuck by leaving out outcomes, assuming all situations are equally likely, or mixing up one outcome with a larger event, like one student versus all girls.
Ways to teach it
- Hands-on activity: Give pairs a spinner split into equal sections, have them list outcomes, then calculate probabilities for specific colors or numbers.
- Writing prompt: Ask, 'How do you know each outcome is equally likely, and when would that assumption be wrong?'
- Quick assessment: Show a bag with 3 red, 3 blue, and 3 green cubes, then ask for three event probabilities.
- Real-world connection: Use a class roster to find the probability of randomly choosing one named student, a seventh grader, or someone with glasses.
Plan a lesson for CCSS.Math.Content.7.SP.C.7a
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Related standards
- CCSS.Math.Content.HSS-CP.B
Use the rules of probability to compute probabilities of compound events in a uniform probability model
- CCSS.Math.Content.7.SP.C.7
Develop a probability model and use it to find probabilities of events. Compare probabilities from a model to observed frequencies; if the agreement is not good...
- CCSS.Math.Content.7.SP.C.7b
Develop a probability model (which may not be uniform) by observing frequencies in data generated from a chance process.
- CCSS.Math.Content.7.SP.C
Investigate chance processes and develop, use, and evaluate probability models.