Skew / Aggregation Layer

Calculate skewness across specified columns, similar to scipy.stats.skew or pandas skew(). Measures the asymmetry of data distribution around its mean.

Mathematical form: $$\text{Skewness}=\frac{{\sum }_{i=1}^n(x_i-\bar{x}{)}^3/n}{s^3}$$ Where:

• $\bar{x}$ is the mean
• $s$ is the standard deviation
• $n$ is the number of observations

Interpretation:

• Positive skew: Long right tail (mean > median)
• Negative skew: Long left tail (mean < median)
• Zero skew: Symmetric distribution

Common applications:

• Financial return analysis
• Process control monitoring
• Medical outcome distributions
• Environmental data analysis
• Population demographics
• Response time studies

Provides a simpler interface for single-column skewness analysis.