Question Details

The demand and forecast of an item for five months are given in the table.

Month Demand
Forecast
April
225
200
May
220 240
June 285 300
July 290 270
August 250 230

The Mean Absolute Percent Error (MAPE) in the forecast is ___________ % (round off to two decimal places)

Month Demand Forecast April 225 200 May 220 240 June 285 300 July 290 270 August 250 230

Show Answer

Correct Answer :

Correct answer is : 8.07

Period

Actual Demand

(Di)

Forecasted Demand

(Fi)

Absolute Percentage

Error

Ei = (Di - Fi)

April

225

200

25

May

220

240

-20

June

285

300

-15

July

290

270

20

August

250

230

20

Mean Absolute Percentage Error (MAPE) :

M A P E = i = 1 n | D i F i D i | n × 100

| 25 225 | + | 20 220 | + | 15 285 | + | 20 290 | + | 20 250 | 5 × 100 = 8.072 %

Solution :

The correct answer is 8.07.

Step-by-Step Explanation:

Mean Absolute Percentage Error (MAPE) is a measure of prediction accuracy of a forecasting method in statistics. It is calculated using the following formula:

M A P E = 1 n i = 1 n | D i F i D i | × 100

where:
- Di is the actual demand for period i,
- Fi is the forecasted demand for period i, and
- n is the total number of periods (n=5 months).

Let's calculate the absolute percentage error for each month:

1. April:
Actual Demand (D1) = 225, Forecast (F1) = 200
Absolute Percentage Error = | 225 200 225 | = | 25 225 | 0.1111

2. May:
Actual Demand (D2) = 220, Forecast (F2) = 240
Absolute Percentage Error = | 220 240 220 | = | 20 220 | 0.0909

3. June:
Actual Demand (D3) = 285, Forecast (F3) = 300
Absolute Percentage Error = | 285 300 285 | = | 15 285 | 0.0526

4. July:
Actual Demand (D4) = 290, Forecast (F4) = 270
Absolute Percentage Error = | 290 270 290 | = | 20 290 | 0.0690

5. August:
Actual Demand (D5) = 250, Forecast (F5) = 230
Absolute Percentage Error = | 250 230 250 | = | 20 250 | = 0.0800

Now, we compute the average of these absolute errors and multiply by 100 to get the percentage value:

M A P E = 0.1111 + 0.0909 + 0.0526 + 0.0690 + 0.0800 5 × 100

M A P E = 0.4036 5 × 100 8.072 %

Rounding to two decimal places, we get 8.07 %.

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