Chapter 6 of Class 11 Economics, titled Correlation, talks about the relationship between two or more variables. It helps us find out whether two things move together and to what extent. For example, is there a connection between study hours and marks? Or rainfall and crop production? This chapter teaches us how to measure and understand such relationships using simple methods like scatter diagrams and Karl Pearson’s coefficient.
I’m writing about this topic because correlation is not just another theoretical concept in economics, but a practical tool that is used everywhere. From students analysing their own performance to government agencies comparing inflation with interest rates – correlation is useful. Knowing how to measure it correctly and interpret its meaning can help students make sense of real-life situations. For exam preparation too, it is a high-scoring chapter with direct formula-based questions. With the help of a simple PDF, you can go through all key concepts and formulas quickly during revisions. That’s why I’ve created this guide.
What is Correlation in Economics?
Correlation means the degree to which two variables move together. If both go up or down together, that’s positive correlation. If one increases while the other decreases, that’s negative correlation. If there is no connection, it’s called zero correlation.
Types of Correlation
- Positive Correlation: Both variables increase or decrease together
Example: Height and weight - Negative Correlation: One increases while the other decreases
Example: Number of hours spent watching TV and exam performance - No Correlation: No pattern in change
Example: Roll number and marks
Methods of Measuring Correlation
1. Scatter Diagram
- A graph with dots showing the relationship between two variables
- Gives a visual idea of how close or far the points are
2. Karl Pearson’s Coefficient
- A mathematical method
- Value lies between -1 and +1
- +1 means perfect positive, -1 is perfect negative, 0 means no correlation
- Formula:
![r = Σ(xy)/√(Σx² × Σy²)] (The formula is fully explained in the NCERT book)
3. Spearman’s Rank Correlation
- Used when data is ranked instead of given in numbers
- Formula uses the difference in ranks to calculate correlation
Importance of Correlation in Real Life
- Used in economics, business, education, and even weather studies
- Helps in understanding relationships before making decisions
- For example, before investing in a sector, we may check correlation between GDP growth and stock market performance
- In schools, teachers can analyse correlation between attendance and results
Download PDF
Click Here to Download NCERT Class 11 Economics Chapter 6: Correlation PDF
