A weighted average is a statistical measure that computes the average of a set of values, assigning different weights to each value based on its significance or importance. In the context of machine learning and data analysis, weighted averages are often used to combine predictions or performance metrics where some elements are considered more influential than others. This approach allows for a more nuanced understanding of data contributions, making it particularly useful in ensemble learning methods and performance evaluation. Weighted averages help practitioners assess model performance more effectively by reflecting the varying importance of different data points or features.