Please answer this using excel.

Quality Bikes is a wholesale firm that specializes in the distribution of bicycles. The

company decides to use a inventory management system to reduce inventory levels

and minimize total variable inventory costs. At the same time, they implement a

computerized forecasting system based on statistical forecasting that considers

seasonal effects. The system is to generate two sets of forecasts$-$one based on the

moving$-$average method, a second based on the exponential smoothing method, and a

third based on exponential smoothing with seasonality. The average of these three

forecasts for each month is to be used for inventory management purposes.

The following table gives the available data on monthly sales of $10-$speed bicycles over

the past three years. The last column also shows monthly sales this year, which is the

first year of operation of the new forecasting system.

a$.(4$ points$)$ Determine the seasonal factors for the $12$ months based on past sales.

b$.(6$ points$)$ After considering seasonal effects, apply the moving$-$average method

based on the most recent three months $(n=3)$ to forecast monthly sales for each month

of this year. Please create a forecasting graph for the moving$-$average forecasting.

c$.(10$ points$)$ After considering seasonal effects, apply the exponential smoothing

method $($Alpha$=0\mathrm{.}4)$ to forecast monthly sales this year. Please create a forecasting

graph for the exponential smoothing forecasting.