To be or not to be... linear

The student will determine the correlation between two variables. They will graph ordered pairs on a coordinate plane, determine a best fit line, find slope and intercepts, and write the equation of a line. This lesson plan is geared for both 8th grade math and algebra.

A lesson plan for grades 8–12 Mathematics

By Kyle Gorton

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• NCDigIns Help students become proficient in mathematics with this formative assessment diagnostic tool.
• Purplemath The lessons on this website help students understand and gain self-confidence in algebra.
• Math Central A rich, comprehensive resource, supported by the University of Regina, Canada, for math students and teachers at mid elementary levels through secondary levels.

Related pages

• Investigating linear equations: Using a graphic calculator to compare the slope and y-intercept of lines to understand the slope-intercept form (y = mx+b) and what effect each has on a line.
• Walk the line: This lesson demonstrates the effects of changing the slope and y-intercept on the graph and equation of a line.
• Graphing quadratic equations: This lesson will help students quickly graph a quadratic equation. It will also help them to understand the purpose of completing the square.

Related topics

• Learn more about algebra, best-fit, data collection, graphing, linear equations, mathematics, and slope.

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Learning outcomes

• Students will understand, identify, and interpret positive, negative, and no correlation for scatter plots.
• Students will be able to graph ordered pairs on a coordinate plane.
• Students will be able to find the slope of a line given the graph.
• Students will correctly find X and Y intercepts from a graph.
• Given the graph of a linear equation students will determine the equation of the line in three forms (slope-intercept, point-slope, and standard).

Teacher planning

Time required for lesson

2 hours

Materials/resources

• Graph paper
• Rulers - small and large may be needed
• Pencils
• Data collection sheets: list format and table format.

Pre-activities

• Students should have been introduced to the concepts of the coordinate plane, graphing linear equations, slope, intercepts, and slope-intercept form.
• Students should be competent in plotting points and data collection.

Activities

1. Students will pick two variables that they think may have a relationship. For Example: Height Vs. Weight, Time at mall Vs. Money spent, Foot size Vs. How high you can jump, Fingernail length Vs. Finger length, etc.
2. Students then need to collect data (the more the merrier). The students/teacher may choose the method that is used to have students collect the data. The teacher may assign the collection process as a homework activity or it could be done during class. Have students collect data in a table or list format (see attached worksheets).
3. Students then need to create a coordinate plane with the X and Y axis labeled with the two chosen variables, an appropriate numbering scale, and a title.
4. Students must plot the given data collection points.
5. After students have plotted their points, students will draw a best fit line for the given data. If the data has no correlation students may draw a line to continue with the forthcoming parts of the lesson.
6. Once the best fit line is drawn students will gather the slope and intercepts from their line. They will then find the equation of the line.
7. Finally, you may have a discussion concerning positive, negative, and no correlation or have students answer the given questions (see Question Sheet attachment)

Assessment

• Student graph and question sheet
• Student discussion in groups using any/all of the prompts given the Discussion Questions.

Supplemental information

Comments

I used this as a project for my Algebra students and they enjoyed it.