Grade Level(s): 9, 10, 11, 12
Internet Connection, Speakers/Headphones, Computer Media Player
Keywords: correlation, causation, correlation coefficient, confounding variables, statistics
Lesson Plan Template: General Lesson Plan
Learning Objectives: What will students know and be able to do as a result of this lesson?
Students will be able to:
- Distinguish between the (correlation coefficient) strength and direction of a relationship between two variables as correlation and not causation.
- Explain that correlation does not imply causation, by investigating confounding variables.
Prior Knowledge: What prior knowledge should students have for this lesson?
Students will need to be able to first know how to:
- Be familiar with reading graphs and positive and negative slope
Guiding Questions: What are the guiding questions for this lesson?
If there is an obvious relationship between two variables, can we say there is a causal link?
Introduction: How will the teacher inform students of the intent of the lesson? How will students understand or develop an investigable question?
Prompt the students with the following scenario:
You are driving down the road and you hear the DJ on the radio say, "New studies prove that people who play computer games earn more money!" What do you think about this claim?
If students have trouble making the connection, ask a follow-up:
- What confounding variable (or outside influence that effects both of those things) could lead the researchers to believe this?
- Students may come up with many answers. The most obvious, is that people who own computers in which to play the games on, have the extra money available to buy the computer in the first place
Discuss how confounding variables can lead people to come to conclusions that may not necessarily be true:
- Eating ice cream causes people to be angry
- People usually eat ice cream in the summertime, and heat (the confounding variable) can cause people to be more irritable
- Coffee causes cancer
- It has been shown that more coffee drinkers (than nondrinkers) smoke cigarettes (the confounding variable
- Working overtime hours causes you to have more health problems
- People who work overtime may not have time (confounding variable) to go to the doctor as often, and therefore may not receive all of the medical attention they may need.
Students will then be shown the Perspectives video "" (CPALMS resource ID 128447)
- Stop the video at 3:52
- Ask the students what situation may have a positive correlation, but not a cause and effect relationship
- Reading ability and height; age is the confounding variable
- Ask the students what situation may have a negative correlation, but not a cause and effect relationship
- Shoe size and bedwetting; again, age is the confounding variable.
- After the video has ended
- Explain to students that even if they may find a strong correlation between two variables, correlation does not imply causation. The only way to truly determine cause and effect is to do a well-controlled experiment, not a survey or an observational study (where you just view the behavior, but you do not administer any treatments to the subjects). Also, these studies are often costly and difficult to perform, especially with people.
Investigate: What will the teacher do to give students an opportunity to develop, try, revise, and implement their own methods to gather data?
Students will be placed into groups of 2-4.
- The students will receive the independent practice sheet and work together to come up with scenarios that may appear to have a cause and effect relationship, but have an outside variable or variables that may lead them to believe that.
- Circulate during the activity and offer and assistance to those in need, asking probing questions to help students improve their methodology.
Analyze: How will the teacher help students determine a way to represent, analyze, and interpret the data they collect?
Have the groups participate in think-pair-share with one another. As a whole class, let them see what confounding variables other groups came up with, give their opinions, and offer suggestions.
Some predictable errors may be:
- If they find a confounding variable that makes sense, students may feel that it must be the cause of the correlation. Confounding variables only give alternate reasons that a relationship may appear, but it still doesn't prove causation.
Closure: What will the teacher do to bring the lesson to a close? How will the students make sense of the investigation?
After the activity is completed:
- Bring the students back together and discuss again about correlation and how it is helpful in statistical studies.
- Reiterate that a strong correlation does not imply causation. Studies can often be very controlled, but still miss some lurking/confounding variable that impacts both the explanatory and response variable.
- Bring up any errors you noticed while checking students' work (keeping the groups/students who made the errors confidential). Address why those errors may have occurred and how to avoid making them in the future.
The students will be given an exit ticket as provided in the resources. Project the following cartoon for the students to see:
Students will need to display their answers on their individual white boards and hold them up so that the teacher can see. They can discuss their answers if need be, and help each other if they are having trouble. They do need to attempt it on their own first.
Monitor the students understanding of the lesson through the independent practice. Provide feedback and offer probing questions when necessary. The discussion during the Analyze and Closure portions of the lesson are very important for the teacher to listen and assess student learning.
Feedback to Students
Students will receive feedback throughout their work. Circulate throughout the investigation to listen to discussions and ask probing question to address any possible misconceptions.
Accommodations & Recommendations
This lesson addresses the following mathematical practices:
- Make sense of problems and persevere in solving them.
- Reason abstractly and quantitatively.
- Construct viable arguments and critique the reasoning of others.
- Model with mathematics.
Source and Access Information
Name of Author/Source: Lauren Henehan
District/Organization of Contributor(s): AlachuaDistrict/Organization of Contributor(s): Alachua
Access Privileges: Public
* Please note that examples of resources are not intended as complete curriculum.