CCSS.Math.Content.8.SP.A.3
The standard
Use the equation of a linear model to solve problems in the context of bivariate measurement data, interpreting the slope and intercept.
Common Core State Standards for Mathematics · Statistics and Probability
What this standard means
Students need to use a line of best fit as a tool, not just draw it. They should plug values into a linear equation, make predictions, and explain what the slope and y-intercept mean in the situation.
Mastery looks like saying, “For each 1 unit increase in x, y changes by this much,” with correct units and context. Students often mix up slope and intercept, treat predictions as exact facts, or give an intercept meaning when x = 0 does not make sense in the situation.
Ways to teach it
- Hands-on: Give students scatterplot cards with equations, and have them match each graph, equation, slope meaning, and intercept meaning.
- Prompt: Explain what the slope and y-intercept mean for a model relating hours studied to test score.
- Quick assessment: Give y = 12x + 40 for bike rental cost, and ask for the cost at 3 hours and both meanings.
- Real-world connection: Use local weather data to model temperature by hour, then discuss what the slope says about warming or cooling.
Plan a lesson for CCSS.Math.Content.8.SP.A.3
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Related standards
- CCSS.Math.Content.HSS-ID.C.7
Interpret the slope (rate of change) and the intercept (constant term) of a linear model in the context of the data.
- CCSS.Math.Content.8.EE.C.8c
Solve real-world and mathematical problems leading to two linear equations in two variables.
- CCSS.Math.Content.HSF-LE.A
Construct and compare linear, quadratic, and exponential models and solve problems
- CCSS.Math.Content.HSS-ID.C
Interpret linear models