Class 11 Maths Chapter 13 Statistics – Revision Notes

Quick revision notes for Class 11 Maths Chapter 13 (Statistics). These Class 11 Maths Chapter 13 notes are ideal for quick revision just before exams.

Measures of Dispersion

• Range = max−min.
• Mean deviation = ∑|xi−mean|/n.
• Variance σ² = ∑(xi−mean)²/n.
• Standard deviation σ = √(variance).

Key Points

• Std dev always ≥ 0; 0 means all values identical.
• Smaller std dev = more consistent/less spread data.
• Std dev preferred over variance (same units as data).

One-Line Summary

Measures of dispersion (range, mean deviation, variance, standard deviation) describe how spread out data is around the mean, with standard deviation being the most widely used since it returns to the data’s original units.

Written by Satish

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