ACT Preparation / Unit 15 ACT 1419 short lesson, about 20 seconds
Correlation
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The idea
The correlation coefficient r runs from −1 to 1. Its sign gives the direction of a linear association, and its size the strength: near ±1 is strong, near 0 weak.
In practice
r = −0.9 is a strong negative linear association; r = 0.1 is weak.
Where people slip
Correlation is not causation: two variables can move together because a third affects both.
Your place on the trail
Every lesson rests on earlier ones and opens later ones. Tap any to jump.
Builds on
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