A weighted average assigns different importance to values. Formula: Σ(value × weight) / Σ(weights). Example: if Test 1 (weight 30%) = 80 and Test 2 (weight 70%) = 90, weighted average = (80×0.3 + 90×0.7) / 1.0 = 87, not the simple average of 85.
How to Use
Add values and their weights:
- Value: The score or amount
- Weight: Importance factor
- Result: Weighted mean computed
Formula
Weighted Average = Σ(xᵢ × wᵢ) / Σ(wᵢ). Weights can be any positive numbers — they'll be normalized to proportions automatically.
Real-World Examples
- Course grades: midterm 30%, final 50%, homework 20%
- Stock portfolio: returns weighted by investment amount
- Customer satisfaction: weighted by response count
Step-by-Step Instructions
- 1Add a value and its weight.
- 2Add more value-weight pairs.
- 3View the weighted average.
- 4Compare with the simple average.
- 5Check contribution percentages.