CCSS.Math.Content.7.SP.A.2
The standard
Use data from a random sample to draw inferences about a population with an unknown characteristic of interest. Generate multiple samples (or simulated samples) of the same size to gauge the variation in estimates or predictions.
Common Core State Standards for Mathematics · Statistics and Probability
What this standard means
Students need to use a random sample to make a reasonable estimate about a larger group. They should know that one sample gives an estimate, not a sure answer. They also need to take or simulate several samples of the same size and compare the results.
Mastery looks like students explaining both their estimate and how much it might vary. They can say, for example, “Most samples gave means between 5.2 and 5.8.” Students often get stuck by using convenience samples, trusting one sample too much, or ignoring sample size.
Ways to teach it
- Hands-on: Give groups a page from a novel, have them randomly select 30 words, then estimate the mean word length for the page.
- Prompt: Would surveying only your friends predict the whole grade’s favorite lunch, and why would a random sample be better?
- Quick check: Show three sample means from the same population and ask students to estimate the population mean and describe possible error.
- Real-world connection: Use a mock school election poll with random student names to predict the winner and discuss how far off it might be.
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Related standards
- CCSS.Math.Content.7.SP.A
Use random sampling to draw inferences about a population.
- CCSS.Math.Content.HSS-IC.B.4
Use data from a sample survey to estimate a population mean or proportion; develop a margin of error through the use of simulation models for random sampling.
- CCSS.Math.Content.HSS-IC.A.1
Understand statistics as a process for making inferences about population parameters based on a random sample from that population.
- CCSS.Math.Content.7.SP.A.1
Understand that statistics can be used to gain information about a population by examining a sample of the population; generalizations about a population from a...