Correlation
Understanding how two variables move together 🔗
1️⃣ What is Correlation?
Correlation tells us:
- Two variables madhya relationship undha?
- Undi ante, same direction aa opposite direction aa?
- Relationship entha strong?
👉 Simple words lo:
“When X changes, does Y also change?”
⚠️ Important:
Correlation ≠ Causation
(Relationship undi ani cause ani kaadu)
2️⃣ Real-World Examples (Student Friendly)
📚
Study & Marks
Hours studied ↑
Marks ↑
Positive correlation
🌡️
Temperature & Jackets
Temperature ↑
Jackets sold ↓
Negative correlation
🎲
Random Variables
Shoe size & IQ
No pattern
No correlation
3️⃣ Types of Correlation
- Positive Correlation (+): X ↑ → Y ↑
- Negative Correlation (–): X ↑ → Y ↓
- Zero Correlation: No relationship
4️⃣ Visual 1: Positive vs Negative Correlation
Dots show data points.
Pattern direction explains correlation.
5️⃣ Visual 2: Strength of Correlation
How tightly points are packed matters.
6️⃣ Correlation Coefficient (r)
Correlation is measured using Pearson’s r.
-1 ≤ r ≤ +1
- r = +1 → Perfect positive
- r = -1 → Perfect negative
- r = 0 → No correlation
Interview Checkpoint 🎯
Correlation vs Regression?
Correlation → relationship strength
Regression → prediction
Does correlation mean causation?
No ❌ Correlation only shows association.
Range of correlation coefficient?
From -1 to +1.