The Volume Weighted Moving Average is a weighted moving average that uses the volume
as the weighting factor, so that higher volume days have more weight. It is a non-cumulative
moving average, in that only data within the time period is used in the calculation.
See also Exponential MA, Least Squares MA, Simple MA, Triangular MA, Weighted MA,
Welles MA, Variable MA, Zero Lag Exponential MA, DEMA, TEMA and T3.