Skewness and Kurtosis Formulas:
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Skewness and kurtosis are statistical measures that describe the shape of a probability distribution. Skewness measures the asymmetry of the distribution, while kurtosis measures the "tailedness" or peakiness of the distribution.
The calculator uses the standard formulas for skewness and kurtosis:
Where:
Explanation: Skewness indicates whether data are skewed left (negative), symmetric (zero), or skewed right (positive). Kurtosis compares the tail heaviness to a normal distribution.
Details: These measures help identify departures from normality, assess risk in financial modeling, and understand data distribution characteristics for proper statistical analysis.
Tips: Enter the third moment (μ₃), fourth moment (μ₄), and standard deviation (σ). All values must be valid with standard deviation greater than zero.
Q1: What does positive skewness indicate?
A: Positive skewness means the distribution has a longer right tail, with most data points concentrated on the left side.
Q2: What is mesokurtic, leptokurtic, and platykurtic?
A: Mesokurtic (kurtosis = 3) is normal distribution, leptokurtic (>3) has heavier tails, platykurtic (<3) has lighter tails.
Q3: When are these measures most useful?
A: In finance for risk assessment, quality control for process monitoring, and any field requiring distribution shape analysis.
Q4: What are the limitations of these measures?
A: They can be sensitive to outliers and may not fully capture complex distribution shapes in small samples.
Q5: How do I interpret kurtosis values?
A: Values > 3 indicate heavier tails than normal, < 3 indicate lighter tails. Excess kurtosis subtracts 3 for comparison to normal distribution.