which assumption do you use for copula method copula is based on what assumption why i.i.d assumption is not necessary for copula function why does copula need iid assumptions why is copula assumption necessary is copula an assumption? what is the i.id assumption for copula what assumptions should be made by copula copula function if data are independent why does copula use iid assumption why should copula function be iid why do copula assumptions need to be made? why copula assumptions why do copula have assumptions why do copula function use marginal distributions why is copula i.i.d. why is copula used does copula use iid assumption why does copula need an i.i.d assumption does copula depend on assumptions