Copula functions as a tool in statistical modeling and simulation

Copulas are functions that join or couple multivariate distribution functions to their one dimensional marginal distribution functions. Alternatively, copulas are multivariate distribution functions whose one-dimensional margins are uniform on the interval (0,1). The appeal of copula function lies in the fact that it eliminates the implied reliance on the multivariate normal or the assumption that dimension are independent. Copula functions provide a convenient way to express joint distributions and simulate correlated variables. Several copulas with varying shapes are available providing flexibility in modelling. We discuss idea of copula functions in statistical modeling and simulation.