Bivariate Data

Lesson 5

Math

Unit 8

8th Grade

Lesson 5 of 9

Objective


Write equations to represent lines fit to data and make predictions based on the line.

Common Core Standards


Core Standards

  • 8.SP.A.3 — Use the equation of a linear model to solve problems in the context of bivariate measurement data, interpreting the slope and intercept. For example, in a linear model for a biology experiment, interpret a slope of 1.5 cm/hr as meaning that an additional hour of sunlight each day is associated with an additional 1.5 cm in mature plant height.

Foundational Standards

  • 8.F.B.4

Criteria for Success


  1. Write an equation in slope-intercept form for a line that represents a trend in data in a scatter plot.
  2. Use the equation of a line of best fit to make predictions about new data.
  3. Understand that predictions based on equations of best fit lines are based on the association between the data and do not represent actual data points. 

Tips for Teachers


Students recall and are re-engaged in their work with linear equations, specifically writing linear equations given a graph or information about the relationship. 

Fishtank Plus

Unlock features to optimize your prep time, plan engaging lessons, and monitor student progress.

Anchor Problems

25-30 minutes


Problem 1

The scatter plot below represents the relationship between a crocodile’s bite force (in pounds) and its body mass (in pounds) for several species of crocodiles. Patti drew a line through the graph to represent the trend in the data points. 

a.   Write an equation to represent the line of best fit that Patti drew for the data.

b.   Using your equation, predict the bite force of a 600-pound crocodile.

Guiding Questions

Create a free account or sign in to access the Guiding Questions for this Anchor Problem.

Student Response

Upgrade to Fishtank Plus to view Sample Response.

References

EngageNY Mathematics Grade 8 Mathematics > Module 6 > Topic C > Lesson 9Exercise 5

Grade 8 Mathematics > Module 6 > Topic C > Lesson 9 of the New York State Common Core Mathematics Curriculum from EngageNY and Great Minds. © 2015 Great Minds. Licensed by EngageNY of the New York State Education Department under the CC BY-NC-SA 3.0 US license. Accessed Dec. 2, 2016, 5:15 p.m..

Modified by Fishtank Learning, Inc.

Problem 2

Jerry forgot to plug in his laptop before he went to bed. He wants to take the laptop to his friend’s house with a full battery. The pictures below show screenshots of the battery charge indicator after he plugs in the computer at 9:11 a.m.

a.   The screenshots suggest an association between two variables. What are the two variables in this situation? 

b.   Make a scatter plot of the data.

c.   Draw a line that fits the data and find the equation of the line.

d.   When can Jerry expect to have a fully charged battery?

Guiding Questions

Create a free account or sign in to access the Guiding Questions for this Anchor Problem.

Student Response

Upgrade to Fishtank Plus to view Sample Response.

References

Illustrative Mathematics Laptop Battery Charge

Laptop Battery Charge, accessed on March 15, 2017, 12:45 p.m., is licensed by Illustrative Mathematics under either the CC BY 4.0 or CC BY-NC-SA 4.0. For further information, contact Illustrative Mathematics.

Problem Set

15-20 minutes


Give your students more opportunities to practice the skills in this lesson with a downloadable problem set aligned to the daily objective.

Target Task

5-10 minutes


The scatter plot below shows the incomes of a sample of people in a town by their number of years of education.

a.   Draw a line through the data points that best represents the trend in the data.

b.   Write the equation for the line you drew.

c.   Someone from this town completed 16 years of education. What prediction can you make about their annual income?

Student Response

Upgrade to Fishtank Plus to view Sample Response.

Additional Practice


The following resources include problems and activities aligned to the objective of the lesson that can be used for additional practice or to create your own problem set.

  • Include review problems for 8.F.4 where students are given graphs or tables and write the equation of the line.
  • Revisit the problems from Lesson 4 where students drew lines to data sets. Have students write the equations for their lines of fit. 

Next

Interpret the slope and $$y$$-intercept of a fitted line in context.

Lesson 6
icon/arrow/right/large

Lesson Map

A7CB09C2-D12F-4F55-80DB-37298FF0A765

Request a Demo

See all of the features of Fishtank in action and begin the conversation about adoption.

Learn more about Fishtank Learning School Adoption.

Contact Information

School Information

What courses are you interested in?

ELA

Math

Are you interested in onboarding professional learning for your teachers and instructional leaders?

Yes

No

Any other information you would like to provide about your school?

We Handle Materials So You Can Focus on Students

We Handle Materials So You Can Focus on Students

We've got you covered with rigorous, relevant, and adaptable math lesson plans for free