Summarize, visualize, and understand data before diving into inference.
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 mean uses algebraic operations; it's sensitive to outliers. The median is more robust. For symmetric distributions, mean ≈ median ≈ mode.
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Mean = 40/5 = 8
Deviations: −4, −1, 0, 2, 3. Squared: 16, 1, 0, 4, 9
Variance = 30/5 = 6. SD = √6 ≈ 2.45
Skewness describes asymmetry: right-skewed (mean > median, long right tail), left-skewed (mean < median). Kurtosis describes tail heaviness. The normal distribution has skewness 0 and kurtosis 3 (by convention, "excess kurtosis" = 0).