Kernel Density Estimation (KDE): A nonparametric method to estimate the probability density function of a random variable by averaging over locally weighted contributions of each data point.

In Excel, syntax for this function is NORMINV (probability,mean,standard deviation). Using the sales example, with a weekly sales average of $2,000 that fluctuates about $500 up or down, you know ...

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.