📚 Key Concepts
Measures of DispersionRangeMean DeviationStandard DeviationVarianceAnalysis of frequency distributionsCoefficient of variationGrouped vs ungrouped data
🎯 Key Formulas
Range = Highest value - Lowest valueMean Deviation = Σ|x - x̄|/nVariance (σ²):- For ungrouped: Σ(x - x̄)²/n
- For grouped: Σf(x - x̄)²/n
Standard Deviation (σ) = √(Variance)Coefficient of Variation = (σ/x̄) × 100%
⚠️ Common Mistakes to Avoid
Wrong class interval selectionIncorrect frequency countError in deviation calculationsWrong formula choice for data typeMistakes in squared deviationsConfusion between σ and σ²
📖 Knowledge Prerequisites
Basic arithmeticMean calculationSquare rootsSummation notationFrequency distribution
💡 Tips for Students
Choose appropriate measureCheck calculations step by stepRemember the difference between σ and σ²Practice with both types of dataAlways verify unitsUse tables for organization
👉 Practice Recommedations
Calculate range for datasetsFind mean deviationCompute standard deviationWork with grouped dataCalculate coefficient of variationCompare different measuresSolve real-world problems
Practice each question with a timer and get instant feedback
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