In a cumulative moving average, the data are added to the data set in an ordered data stream over time. The objective is to compute the average of all the data at each point in time when new data arrived. For example, an investor may want to find the average price of all of the stock transactions for a particular stock over time, up to the current time.
The cumulative moving average computes the arithmetic average of all the rows from the beginning of the series, using this formula:
CMAVG = SUM(a1, ..., aN)/N
N is the number of rows from the beginning of the data set.