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Log-Normal Distribution

A right-skewed continuous distribution used for positive variables whose logarithm is normally distributed.

The log-normal distribution is well suited for modeling positive-valued processes that grow through multiplicative effects. Income, duration, file size, waiting time, and some biological quantities may follow this kind of distribution. Because it has a long right tail, it is also useful for understanding outlier behavior. In machine learning, it can matter in data transformations and target variable modeling. It provides a strong explanation for why log transformations often work well in practice.