# WHY EWM CHOSEN OVER WM

## WHY EWM CHOSEN OVER WM

1. What is EWM and WM?
• What is EWM
• What is WM
2. EWM vs WM: Comparative Analysis
• Forecasting Accuracy
• Data Requirements
• Computational Complexity
• Suitability for Different Situations
3. Detailed Discussion on the Superiority of EWM
• Reduced Sensitivity to Outliers
• Robustness in Non-Stationary Environments
4. Practical Examples of EWM's Effectiveness
• Demand Forecasting in Retail
• Stock Market Price Prediction
• Inventory Management
5. When WM is the Better Choice
• Long-term Forecasting
• Situations with Consistent Trends
• Availability of Historical Data
6. Conclusion

What is EWM and WM?

Exponential Weighted Moving Average (EWM) and Weighted Moving Average (WM) are two widely used techniques in time series analysis and forecasting. These methods help uncover patterns and trends in historical data to make informed predictions about future values. Let's explore each technique in detail:

What is EWM?
EWM, also known as exponentially smoothed weighted average, assigns exponentially decreasing weights to past observations as we move further back in time. This means recent data has a more significant influence on the forecast, while older data gradually fades in importance. This characteristic makes EWM highly responsive to recent trends and changes in the data.

What is WM?
WM, on the other hand, assigns equal weights to all past observations within a specified window. It calculates the average of the most recent n values, where n is the window size. WM is less sensitive to recent fluctuations and provides a smoother forecast compared to EWM.

EWM vs WM: Comparative Analysis

To understand why EWM is often chosen over WM, let's compare them based on several key factors:

Forecasting Accuracy:
EWM generally outperforms WM in terms of forecasting accuracy, especially when there are rapid changes or trends in the data. Its ability to assign higher weights to recent observations allows it to capture these changes more effectively.

Data Requirements:
EWM requires less historical data compared to WM. This is because EWM focuses on recent observations, making it more suitable for situations with limited data availability.

Computational Complexity:
Both EWM and WM have relatively low computational complexity, making them easy to implement and use. However, EWM may be slightly more computationally intensive due to the exponential weighting scheme.

Suitability for Different Situations:
EWM is more appropriate when:

• There are rapid changes or trends in the data.
• Recent observations are more relevant for forecasting.
• There is limited historical data available.

WM is more suitable when:

• Long-term forecasting is required.
• The data exhibits consistent trends or patterns.
• There is an abundance of historical data.

Detailed Discussion on the Superiority of EWM

In many practical scenarios, EWM offers several advantages over WM:

EWM's exponential weighting scheme allows it to adapt quickly to sudden shifts or changes in the data. This makes it ideal for forecasting in dynamic environments where trends can change rapidly.

Reduced Sensitivity to Outliers:
EWM's decreasing weights for older observations help reduce the impact of outliers or extreme values on the forecast. This makes it more robust in the presence of noisy or volatile data.

Robustness in Non-Stationary Environments:
EWM is more robust in non-stationary environments, where the mean and variance of the data change over time. Its ability to adapt to changing trends and patterns makes it suitable for forecasting in such scenarios.

Practical Examples of EWM's Effectiveness

EWM has proven its effectiveness in various practical applications:

Demand Forecasting in Retail:
EWM is widely used in retail to forecast demand for products. Its ability to capture recent trends and adapt to changing consumer preferences makes it a valuable tool for inventory management and sales planning.

Stock Market Price Prediction:
EWM is employed by financial analysts to predict stock market prices. Its responsiveness to recent market movements and trends helps them make informed investment decisions.

Inventory Management:
EWM is used in inventory management to forecast future demand and optimize stock levels. Its ability to account for changing demand patterns helps businesses maintain optimal inventory levels and reduce the risk of stockouts or overstocking.

When WM is the Better Choice

While EWM is often the preferred choice, WM may be more suitable in certain situations:

Long-term Forecasting:
For long-term forecasting, WM's ability to provide a smoother forecast may be more appropriate. It can help identify underlying trends and patterns that may not be visible with EWM's focus on recent observations.

Situations with Consistent Trends:
In scenarios where the data exhibits consistent trends or patterns, WM's equal weighting of past observations can provide accurate forecasts. Its less responsive nature helps filter out short-term fluctuations and highlight long-term trends.

Availability of Historical Data:
If there is an abundance of historical data available, WM can leverage this data to provide more robust and reliable forecasts. Its ability to incorporate a larger dataset can help mitigate the impact of random fluctuations and improve forecasting accuracy.

Conclusion

EWM and WM are powerful techniques for time series analysis and forecasting. While both methods have their strengths and weaknesses, EWM often emerges as the preferred choice due to its adaptability to rapid changes, reduced sensitivity to outliers, and robustness in non-stationary environments. Its effectiveness has been demonstrated in various practical applications, making it a valuable tool for businesses and analysts seeking to make informed decisions based on historical data.

1. What is the key difference between EWM and WM?

• EWM assigns exponentially decreasing weights to past observations, while WM assigns equal weights to all past observations within a specified window.
2. When should EWM be used over WM?

• EWM is preferred when there are rapid changes or trends in the data, limited historical data is available, or the data is noisy or volatile.
3. When should WM be used over EWM?

• WM is preferred for long-term forecasting, situations with consistent trends or patterns, or when there is an abundance of historical data available.
4. Which method is more computationally complex?

• EWM is slightly more computationally intensive due to its exponential weighting scheme, but both methods have relatively low computational complexity.
5. Can EWM and WM be combined for better results?

• Yes, combining EWM and WM can sometimes yield improved forecasting accuracy. This hybrid approach can leverage the strengths of both methods, but it requires careful tuning and validation to achieve optimal results.