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# Graphing Slope-Intercept

### Overview

In this PhET activity, students explore the slope-intercept form of a line and connect the slope and y-intercept to the equation of the line. The learning goals for this activity will be to graph a line given an equation in slope-intercept form, write an equation in slope-intercept form given a graphed line, predict how changing the values in a linear equation will affect the graphed line, and predict how changing the graphed line will affect the equation. This activity can be used to help teach a lesson on graphing linear equations. This PheET activity can be downloaded and assigned to Google Classroom.

## UP:MA19.GDA.15

### Vocabulary

• Quantitative variables
• Scatter plot
• Residuals
• Slope
• Rate of change
• Intercepts
• Constant
• Ordered pairs
• Horizontal lines
• Vertical lines

### Knowledge

Students know:
• Techniques for creating a scatter plot.
• Techniques for fitting a linear function to a scatter plot.
• Methods to find the slope and intercept of a linear function.
• Techniques for fitting various functions (linear, quadratic, exponential) to data.
• Methods for using residuals to judge the closeness of the fit of the function to the original data.

### Skills

Students are able to:
• Accurately create a scatter plot of data.
• Correctly choose a function to fit the scatter plot.
• Make reasonable assessments on the fit of the function to the data by examining residuals.
• Accurately fit a linear function to data when there is evidence of a linear association.
• Accurately fit linear functions to scatter plots.
• Correctly find the slope and intercept of linear functions.
• Justify and explain the relevant connections slope and intercept of the linear function to the data.

### Understanding

Students understand that:
• Functions are used to create equations representative of ordered pairs of data.
• Residuals may be examined to analyze how well a function fits the data.
• When a linear association is suggested, a linear function can be fit to the scatter plot to aid in modeling the relationship.
• Linear functions are used to model data that have a relationship that closely resembles a linear relationship.
• The slope and intercept of a linear function may be interpreted as the rate of change and the zero point (starting point).

### CR Resource Type

Learning Activity

PhET