Mathematics · Class 11
Statistics
Learn Statistics with notes, examples, and practice questions.
2 sections15–25 min read6 MCQs · 2 examples
Chapter Overview
Descriptive statistics: measures of central tendency, dispersion, and correlation for bivariate data — mean, median, mode, variance, standard deviation.
Measures
Mean
x̄ = Σxᵢ/n
Variance
σ² = Σ(xᵢ−x̄)²/n
SD
σ = √variance
Correlation
r = Σ(xᵢ−x̄)(yᵢ−ȳ) / √[Σ(xᵢ−x̄)²·Σ(yᵢ−ȳ)²]
Solved Examples
Step-by-step solutions — read each step before checking the final answer.
Mean
Data: 2,4,6,8.
- 120/4=5
Answer
5
Variance
Same data.
- 1Deviations −3,−1,1,3; squared sum/4=5
Answer
σ²=5, σ=√5
Key Points to Remember
- ✓ Grouped data: use class marks
- ✓ Median for even n: average of middle two
- ✓ r between −1 and 1
Exam Tips
- • Use shortcut formulas for frequency data
- • State units for SD
Practice MCQs — Statistics
Test your understanding with topic-wise multiple choice questions. Explanations appear after each answer.
Question 1 of 6Score: 0/0
Mean of 5,10,15: