The idea behind moving average is very simple. It used to be quite cumbersome for older generations of calculator to do this sort of calculation. With modern models, this is a piece of cake as the List feature is almost becoming a standard feature.
For the popular TI-84 series, the list feature can be used to store values into variables. Not only can the list be named, the name assigned can also consist of multiple characters. With the list defined, the moving averages can easily be calculated with arbitrary parameters.
On the financial model arena, the HP17bII+ is a special breed alongside its popular and successful line of signature financial calculator HP12c. The manual for the 17b provided an example that make use of the built-in solver for this. The menu driven 17b is quite convenient to use.