Lesson 7
Fitted values and residuals
Big question
How do we compare what the model predicts with what actually happened?
Lesson progress
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Big question
Concept
Activity
Quiz
Learning objectives
- Explain fitted values and residuals in plain language.
- Use the main concept correctly.
- Connect the lesson idea to a formula, graph, Python result, or real example.
Simple explanation
How do we compare what the model predicts with what actually happened?
Key terms
Example
How do we compare what the model predicts with what actually happened?
Python walkthrough
Interactive activity
Residual calculator
Residual = actual y - predicted y.
Residual = -2.98. The model overpredicted.
Try it yourself
Calculate the residual when actual wage is 24.20 and predicted wage is 27.18.
Common mistakes
Check these before you move on.
The error term is unobserved in the population model. The residual is calculated after estimating the model.
Quick quiz
What is the main idea of Fitted values and residuals?
Key takeaway
Use this lesson idea in a cautious, evidence-based regression interpretation.