Burger Lover Restaurant forecasts weekly sales of cheeseburgers. The last five weeks of actual sales and forecasted sales are provided in the table.

(a) Construct a spreadsheet model to compute the forecast error for each week. The forecast error is defined to be the actual sales minus the forecasted sales and can be positive or negative.
(b) Explain the meaning of positive and negative forecast errors.
(c) Expand the model to calculate what is known as the mean absolute deviation, or MAD, which is a common measure of forecast accuracy. MAD is calculated as MAD Σ|ei|/n, where ei is the forecast error for week i and n is the total number of forecast errors calculated.
(d) Expand the model to calculate what is known as the root mean squared error, or RMSE, which is a common measure of forecast accuracy. RMSE is calculated as RMSE = √Σe2i/n where ei is the forecast error for week i and n is the total number of forecast errors calculated.
(e) Expand the model to calculate what is known as the mean absolute percent error, or MAPE, which is a common measure of forecast accuracy. MAPE is essentially the average percentage forecast error and is calculated as

where ei is the forecast error for week i, yi is the actual value for week i, and n is the total number of forecast errorscalculated.

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Week Actual Sales Forecast Sales 354 367 322 356 320 340 380 366 330 MAPE = Σ(lelly)