If the actual demand of a product is 62, a previous year's forecast is 57, and the value of smoothing constant is 0.3, what would be the forecast for the current year using exponential smoothing method of forecasting?
58.5
Understanding Exponential Smoothing in Forecasting
Exponential smoothing is a popular time series forecasting method. It produces a forecast based on a weighted average of the actual demand in the previous period and the forecast from the previous period. This method gives more weight to recent data, with the degree of weighting determined by a smoothing constant.
Formula for Exponential Smoothing Forecast
The formula used for calculating the forecast for the current period (F_t) using the exponential smoothing method is:
$$F_t = F_{t-1} + \alpha(D_t - F_{t-1})$$
Where:
- \( F_t \) = Forecast for the current period
- \( F_{t-1} \) = Forecast for the previous period
- \( D_t \) = Actual demand for the current period
- \( \alpha \) = Smoothing constant (a value between 0 and 1)
Applying the Exponential Smoothing Formula
In this specific forecasting problem, we are given the following values:
- Actual demand for the current year (\( D_t \)) = 62
- Previous year's forecast (\( F_{t-1} \)) = 57
- Smoothing constant (\( \alpha \)) = 0.3
We need to calculate the forecast for the current year (\( F_t \)) using the exponential smoothing formula.
Step-by-Step Forecast Calculation
Let's substitute the given values into the exponential smoothing formula:
$$F_t = F_{t-1} + \alpha(D_t - F_{t-1})$$
$$F_t = 57 + 0.3(62 - 57)$$
First, calculate the difference between the actual demand and the previous forecast:
$$D_t - F_{t-1} = 62 - 57 = 5$$
Now, multiply this difference by the smoothing constant (\( \alpha \)):
$$\alpha(D_t - F_{t-1}) = 0.3 \times 5 = 1.5$$
Finally, add this result to the previous year's forecast:
$$F_t = 57 + 1.5$$
$$F_t = 58.5$$
Therefore, the forecast for the current year using the exponential smoothing method is 58.5.
Result Comparison
Comparing our calculated forecast of 58.5 with the given options:
- Option 1: 58.5
- Option 2: 60
- Option 3: 62.5
- Option 4: 65
Our calculated value matches Option 1.
Important Questions from Forecasting
Name the human resource demand (need) forecasting technique, which solicits estimates of personnel needs from a group of experts, usually managers. The HRP experts act as intermediaries, summarise the various responses and report the findings back to the experts. The experts are surveyed again after they receive this feedback. Summaries and surveys are repeated until the experts' opinions begin to agree. The agreement reached is the forecast of the personnel needs.
Select the correct option :
The sensitivity of forecast in simple moving average forecasting method, for the increase of the length of average period,
For a product, the forecast and the actual sales for December 2008 were 25 and 20 respectively. If the exponential smoothing constant (α) is taken as 0.2, the forecast sales for January 2009 would be.
For a product the forecast and actual sales for December 2002 were 25 and 20 respectively. If the exponential smoothing constant is taken as 0.2, then forecast sale for January 2003 would be
- The difference between the actual demand for any time period and the forecast for the same period is termed as _______.
