Moving averages visualize the average price of a financial instrument over a specified period of time. However, there are a few different types of moving averages. They typically differ in the way that different data points are weighted or given significance. A Simple Moving Average (SMA) is an unweighted moving average. This means that each period in the data set has equal importance and is weighted equally. As each period ends, the oldest data point is dropped and the newest one is added to the beginning. Please note that of all the moving averages the SMA lags price the most.
about Simple Moving Average.