D. O. Loftsgaarden, C. P. Quesenberry, A Nonparametric Estimate of a Multivariate Density Function, The Annals of Mathematical Statistics, Vol. 36, No. 3 (Jun., 1965 ...

A non-Bayesian derivation of the predictive estimate of a multivariate normal density function is given. The estimate is obtained as best invariant estimate in terms of a goodness-of-fit criterion ...

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.