Probability density function is a statistical expression defining the likelihood of a series of outcomes for a continuous variable, such as a stock or ETF return.

The problem of estimating a probability density function has only recently begun to receive attention in the literature. Several authors [Rosenblatt (1956), Whittle (1958), Parzen (1962), and Watson ...

Asymptotic properties of estimates of a probability density function and its derivatives which use the kernel-method are studied. Some results on the rate of convergence of these estimates are ...