The cumulative moving average, also known as the running average, is calculated by adding all of the data points up to a certain point in time and dividing by the number of data points. The formula for calculating a cumulative moving average is:
CMA = (Sum of data points up to a specific point in time) / (Number of data points up to that point in time)
For example, the cumulative moving average of a stock's closing price on day 20 would be calculated by adding the closing prices of days 1 through 20 and dividing by 20.
With MAvgType ('C'), the MovingAverage function computes the arithmetic average of all the rows from the beginning of the series with this formula:
CMA = (V1 + V2 + ... + VN)/N
Vi is a value. N is the number of rows from the beginning of the data set.