Grade 8 Pre-Algebra (Common Core Mathematics 8 (CCM-8)) Starting Points
Unit 4: Patterns of Association
Essential Questions:
o Visually, how do a non-linear association and a linear association differ on a scatter plot?
o What can data clustering reveal on a scatter plot?
o When estimating line of best fit, how should the line be positioned?
o What does the line of best fit represent?
o How can the line of best fit be used to make predictions about a set of data?
o What kind of data is displayed in a two-way table?
o What types of information can be gathered from a two-way table?
Curriculum Standards:
Investigate patterns of association in bivariate data.
1. Construct and interpret scatter plots for bivariate measurement data to investigate
patterns of association between two quantities. Describe patterns such as
clustering, outliers, positive or negative association, linear association, and
nonlinear association.
2. Know that straight lines are widely used to model relationships between two
quantitative variables. For scatter plots that suggest a linear association, informally
fit a straight line, and informally assess the model fit by judging the closeness of the
data points to the line.
3. Use the equation of a linear model to solve problems in the context of bivariate
measurement data, interpreting the slope and intercept.
4. Understand that patterns of association can also be seen in bivariate categorical
data by displaying frequencies and relative frequencies in a two-way table.
Construct and interpret a two-way table summarizing data on two categorical
variables collected from the same subjects. Use relative frequencies calculated for
rows or columns to describe possible association between two variables.
Approximate Length of Unit: 20 days
Standard(s)
8.SP.A.1, 2
Days
8-10
Notes
Big ideas:
Construct scatter plots and describe the patterns
between quantities.
Use vocabulary such as clustering, outliers,
positive/negative/linear/non-linear association to
describe the graphs
Informally find the line of best fit and use it to make
predictions about data
Resources:
 Task: What is the Relationship
 Online: Graph Creator
 Lesson: Line of Best Fit
 Illuminations Lesson: Line of Best Fit
Assessment Items:
 Illustrative Mathematics: Texting and Grades 1,
Hand Span and Height, Animal Brains, Birds’
Eggs
8.SP.A.3
4-5
Big ideas:
Write equations for line of best fit (estimated)
Use equations to solve and interpret real-world
scenarios
8.SP.A.4
3-5
Resources:
 Lesson: Using and Interpreting Linear Models
 Task: Obesity Rates
 Online Practice: Writing Equations for Line of
Best Fit
Assessment Items:
Illustrative Mathematics: US Airports-Assessment
Variation
Big ideas:
Construct and interpret two-way tables summarizing
two categorical variables
Understand that there can be a pattern of association in
categorical data as well as numerical data
Resources:
 Illustrative Math: Music and Sports
Assessment Items:
 Illustrative Mathematics: What’s Your Favorite
Subject
This document represents one sample starting points for the unit. It is not allinclusive and is only one planning tool. Please refer to the wiki for more information
and resources.