The mathematical purpose of this lesson is to understand that the relationship between variables can be, but is not always, a causal relationship. A causal relationship is one in which a change in one of the variables directly causes a change in the other variable. The work of this lesson connects to previous work because students interpreted the relationship between two variables using the correlation coefficient. The work of this lesson connects to upcoming work because students will analyze bivariate data and draw conclusions from their analysis.
When students determine that there is a causal relationship, they are attending to precision (MP6), because they are refining their language to be more precise. When students analyze the relationship between two variables to determine whether they are causal or not, they are modeling with mathematics (MP4).
Lesson overview
 9.1 Warmup: Used Car Relationships (5 minutes)
 9.2 Activity: Cause or Effect? (15 minutes)

9.3 Activity: Find Your Cause (10 minutes)
 Includes "Are you Ready for More?" extension problem
 Lesson Synthesis
 9.4 Cooldown: Just Cause (5 minutes)
Learning goals:
 Describe (orally and in writing) the strength and sign of the relationship between two variables.
 Investigate the relationship between two variables to analyze whether or not the relationship is causal.
Learning goals (student facing):
 Let’s get a closer look at related variables.
Learning targets (student facing):
 I can look for connections between two variables to analyze whether or not there is a causal relationship.
Glossary:
 causal relationship  A relationship is one in which a change in one of the variables causes a change in the other variable.
 Access the complete Algebra 1 Course glossary.
Standards:
 This lesson builds on the standard: CCSS.HSSID.B.6MS.SID.6MO.A1.DS.A.5a
 This lesson builds towards the standard: CCSS.HSSID.C.9MS.SID.9MO.A1.DS.A.8
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