GATE 2021 ME (ME2) – Question 53
The demand and forecast of an item for five months are given in the table.
| Month | April | May | June | July | August |
|---|---|---|---|---|---|
| Demand | 225 | 220 | 285 | 290 | 250 |
| Forecast | 200 | 240 | 300 | 270 | 230 |
The Mean Absolute Percent Error (MAPE) in the forecast is _____ % (round off to two decimal places).
Practise this question in The GATE Grind →
Show answer and explanation
Correct answer: 8.03 to 8.11
Explanation
MAPE averages absolute error divided by actual demand: $\frac{100}{5}(25/225+20/220+15/285+20/290+20/250)$.
This gives **8.07%**. Divide each month’s error by its own actual demand; neither signed averaging nor a common denominator gives MAPE.