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38What is Central Tendency?
39The Mean (Arithmetic Average)
40The Median: Middle Value
41The Mode: Most Frequent Value
42Comparing Mean, Median, and Mode
43Weighted Mean and Its Applications
44Geometric and Harmonic Means
45Central Tendency for Grouped Data
46What is Variability?
47Range: The Simplest Measure
48Variance: Average Squared Deviations
49Standard Deviation: Interpretable Spread
50Population vs Sample Variance
51Interquartile Range (IQR)
52Mean Absolute Deviation (MAD)
53Coefficient of Variation
54When to Use Each Measure
55Visualizing Spread
56Understanding Percentiles and Their Interpretation
57Quantiles: Quartiles, Deciles, and Beyond
58Calculating Percentiles: Methods and Algorithms
59The Five-Number Summary and Box Plots
60Percentile Rank and Position in Distributions
61Using Percentiles for Comparison and Benchmarking
62Percentiles vs Z-Scores: Complementary Position Measures
63Understanding Distribution Shape
64Skewness: Definition and Interpretation
65Calculating Skewness
66Kurtosis: Definition and Interpretation
67Calculating Kurtosis
68Practical Implications of Shape Measures
69What Are Outliers and Why Do They Matter?
70Visual Methods: Box Plots and Scatter Plots
71Z-Score Method for Outlier Detection
72IQR Method and Tukey's Fences
73Modified Z-Score Using MAD
74Multivariate Outlier Detection
75Domain-Specific Outlier Rules
76Deciding What to Do with Outliers

38What is Central Tendency?
39The Mean (Arithmetic Average)
40The Median: Middle Value
41The Mode: Most Frequent Value
42Comparing Mean, Median, and Mode
43Weighted Mean and Its Applications
44Geometric and Harmonic Means
45Central Tendency for Grouped Data
46What is Variability?
47Range: The Simplest Measure
48Variance: Average Squared Deviations
49Standard Deviation: Interpretable Spread
50Population vs Sample Variance
51Interquartile Range (IQR)
52Mean Absolute Deviation (MAD)
53Coefficient of Variation
54When to Use Each Measure
55Visualizing Spread
56Understanding Percentiles and Their Interpretation
57Quantiles: Quartiles, Deciles, and Beyond
58Calculating Percentiles: Methods and Algorithms
59The Five-Number Summary and Box Plots
60Percentile Rank and Position in Distributions
61Using Percentiles for Comparison and Benchmarking
62Percentiles vs Z-Scores: Complementary Position Measures
63Understanding Distribution Shape
64Skewness: Definition and Interpretation
65Calculating Skewness
66Kurtosis: Definition and Interpretation
67Calculating Kurtosis
68Practical Implications of Shape Measures
69What Are Outliers and Why Do They Matter?
70Visual Methods: Box Plots and Scatter Plots
71Z-Score Method for Outlier Detection
72IQR Method and Tukey's Fences
73Modified Z-Score Using MAD
74Multivariate Outlier Detection
75Domain-Specific Outlier Rules
76Deciding What to Do with Outliers

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Lesson 48 of 2,145·2. Descriptive Statistics FoundationsPro lesson

Variance: Average Squared Deviations

Define variance as the mean of squared deviations from the mean, and understand its units.

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