Hansen's Inequality is a mathematical concept that relates to the field of statistics and economics. It provides a way to compare the expected value of a function of a random variable with the function of the expected value of that variable. This inequality is particularly useful in decision theory and risk assessment, as it helps to understand how uncertainty affects outcomes. The inequality is named after the economist Lars Peter Hansen, who contributed significantly to the understanding of asset pricing and economic dynamics. Hansen's Inequality is often applied in various areas, including finance and econometrics, to analyze the behavior of complex systems under uncertainty.