Lesson 2: Ice Cream and Sunburns

About 30 minutes — Activity-based lesson

What You Will Learn

This lesson covers:

The ice cream-sunburn correlation: both go up in summer
The hidden third variable: hot weather causes both
What a confounding variable is
Activity: match 5 correlations to their hidden third variables

The ice cream-sunburn correlation: both go up in summer

This section covers the key ideas about the ice cream-sunburn correlation: both go up in summer. Discuss with your group or family and explore the concepts together.

The hidden third variable: hot weather causes both

This section covers the key ideas about the hidden third variable: hot weather causes both. Discuss with your group or family and explore the concepts together.

What a confounding variable is

This section covers the key ideas about what a confounding variable is. Discuss with your group or family and explore the concepts together.

Activity: match 5 correlations to their hidden third variables

This section covers the key ideas about activity: match 5 correlations to their hidden third variables. Discuss with your group or family and explore the concepts together.

Check Your Understanding

1. Does ice cream cause sunburns?

Answer: No! Both increase in summer because of a hidden third variable: hot sunny weather. People buy more ice cream AND get more sunburns when it is hot and sunny.

2. What is a confounding variable?

Answer: A hidden third factor that causes both things you are measuring to change. It creates a fake-looking relationship between two things that are not actually connected.

3. How do you find confounding variables?

Answer: Ask: Is there something else that could cause BOTH of these things to change? If yes, that might be the real explanation for the correlation.

4. Why is this mistake so common?

Answer: Because our brains naturally look for cause and effect. When we see two things happening together, we assume one causes the other. But correlation is not causation.

Key Takeaways

The ice cream-sunburn correlation: both go up in summer
The hidden third variable: hot weather causes both
What a confounding variable is
Activity: match 5 correlations to their hidden third variables

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