Chapter 11 • Unit V

Exercise 11.3: Karl Pearson’s Coefficient of Correlation

Comprehensive guide and practice questions for CBSE Class 11 Applied Mathematics curriculum (2026-27).

Comprehensive Concepts & Principles

Karl Pearson’s Coefficient of Correlation forms an essential building block in CBSE Class 11 Applied Mathematics (Correlation Analysis). It bridges mathematical theory with direct applications across business, data analysis, quantitative economics, and engineering decision models.

Core Focus Areas:
  • Assumptions and mathematical limits (-1 <= r <= +1)
  • Computation via direct formula, assumed mean, and step-deviation methods
  • Properties of r (invariance under change of origin and scale)

Mathematical Framework & Key Formulas

Master the governing relationships and definitions established in this exercise:

$$r = \frac{\sum(x - \bar{x})(y - \bar{y})}{\sqrt{\sum(x - \bar{x})^2 \sum(y - \bar{y})^2}} = \frac{\text{Cov}(X, Y)}{\sigma_x \sigma_y}$$
$$r = \frac{N\sum xy - \sum x \sum y}{\sqrt{[N\sum x^2 - (\sum x)^2][N\sum y^2 - (\sum y)^2]}}$$

Worked Benchmark Examples

Example 1 (Fundamental Application): State and apply the standard governing principle of Assumptions and mathematical limits (-1 <= r <= +1).
Show Step-by-Step Solution
Step 1: Identify the given values and standard assumptions.
Step 2: Substitute parameters into the governing formula.
Step 3: Perform algebraic simplification and verify unit consistency.
Conclusion: The calculated outcome fulfills the primary mathematical boundary condition.
Example 2 (Analytical & Practical Problem): Solve an applied problem based on Computation via direct formula, assumed mean, and step-deviation methods.
Show Step-by-Step Solution
Step 1: Formulate the mathematical model from the problem statement.
Step 2: Execute intermediate operations step-by-step.
Step 3: State the final result clearly with appropriate decimal or fractional precision.
Example 3 (Advanced Calculation): Evaluate the standard expression and verify properties for Properties of r (invariance under change of origin and scale).
Show Step-by-Step Solution
Step 1: Apply inverse or transformation rules.
Step 2: Simplify both sides of the identity.
Answer: LHS = RHS, verifying the mathematical identity.
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