How to calculate the weighted average？

The formula for calculating a weighted average is:

Weighted Average = (Sum of (Weighted Value x Weight) / Sum of Weights)

Where:

- Weighted Value: The value of each data point multiplied by its weight
- Weight: The importance or significance of each data point
- Sum of (Weighted Value x Weight): The total of all the weighted values multiplied by their respective weights
- Sum of Weights: The total of all the weights

Here's an example:

Suppose you have three grades: 80, 90, and 95. The weights for each grade are 20%, 30%, and 50%, respectively. To calculate the weighted average, you would use the following formula:

Weighted Average = (80 x 0.2) + (90 x 0.3) + (95 x 0.5) / (0.2 + 0.3 + 0.5)

Weighted Average = 16 + 27 + 47.5 / 1

Weighted Average = 90.5

Therefore, the weighted average of the three grades is 90.5.