Power

Power(min,shape)\underline{\operatorname{Power}}(\mathrm{min}, \mathrm{shape})
  • min\mathrm{min}: minimum value (lower bound, min>0\mathrm{min} > 0)
  • shape\mathrm{shape}: shape parameter (α>0\alpha > 0, controls tail heaviness; smaller values = heavier tails)

  • Formation: follows a power-law relationship where large values are rare but possible.
  • Origin: historically called Pareto distribution after Vilfredo Paretos work on wealth distribution.
  • Rename Motivation: renamed to Power\underline{\operatorname{Power}} to reflect its connection with power-law.
  • Properties: exhibits scale invariance and extremely heavy tails.
  • Applications: wealth distribution, city population sizes, word frequencies, earthquake magnitudes, website traffic.
  • Characteristics: infinite variance for many parameter values; extreme outliers are common.
  • Caution: traditional variance-based estimators completely fail; robust estimators are essential for reliable analysis.