DS StatisticsLesson 16Free preview
Stat Correlation
This lesson is part of Data Science · All levels
Summary
Correlation measures the strength and direction of a linear relationship between two numerical variables, expressed in Pearson coefficients between -1 and +1. A positive value means that both variables move in the direction, a negative value means that they are inversely proportional, and a value near zero means that there is almost no linear relationship. Correlation was the first tool before the regression model was built.
Key points
- Pearson coefficients range from -1 to +1.
- A positive correlation: one goes up, the other goes up.
- Negative correlation: one goes up, the other goes down.
- Approaching zero means no meaningful linear relationship.
- Correlation measures association, not cause.
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