Forecasts and actual sales of portable CD players at Just Say Music are as follows:

Month Forecast Actual Sales

March $150170$

April $220229$

May $205192$

June $256271$

July $250238$

August $260255$

September $270290$

October $280279$

November $296301$

Plot the data and provide insights about the time series.

What is the forecast for December, using a three$-$period moving average?

What is the forecast for December, using a four$-$period moving average?

Compute the MAD, and MAPE for parts b and c and compare your results.