📖 Explanation
Alright, let's break down this demand forecasting problem using the Exponential Smoothing method. This method helps us predict future demand by giving more weight to recent actual demand and less to older forecasts.
The core formula for exponential smoothing is:
Ft+1=αDt+(1−α)Ft
Where:
- Ft+1 is the forecast for the next period (what we want to predict).
- Dt is the actual demand that occurred in the current period.
- Ft is the forecast that was made for the current period.
- α (alpha) is the smoothing constant, which tells us how much importance to give to the latest actual demand. A higher α means we react more quickly to recent changes.
From the question, we are given:
- Smoothing constant, α=0.2.
- Actual demand for Week 4, D4=439 units.
- Forecasted demand for Week 3, F3=500 units.
- Actual demand for Week 3, D3=592 units.
Our goal is to find the forecast for Week 5 (F5). To do this, we first need to calculate the forecast for Week 4 (F4).
Step 1: Calculate Forecast for Week 4 (F4)
Using the formula with t=3 (Week 3), we'll use D3 and F3 to find F4:
F4=αD3+(1−α)F3
F4=(0.2×592)+(1−0.2)×500
F4=(118.4)+(0.8×500)
F4=118.4+400
F4=518.4 units
Step 2: Calculate Forecast for Week 5 (F5)
Now that we have F4, we can use the actual demand for Week 4 (D4) and our calculated F4 to find F5. Here, t=4:
F5=αD4+(1−α)F4
F5=(0.2×439)+(1−0.2)×518.4
F5=(87.8)+(0.8×518.4)
F5=87.8+414.72
F5=502.52 units
Step 3: Final Integer Forecast
The question asks for the forecast in integer form. Rounding 502.52 to the nearest integer, we get 503.
Therefore, the forecasted demand for Week 5 is 503 units.