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Weighted Mean Calculator

Calculate Weighted Average with Step-by-Step Derivation

Values (separated by commas)
Weights (separated by commas, same count as values)

Weighted Mean Formula

Weighted Mean W = Σ(wᵢ × xᵢ) / Σ(wᵢ)
wᵢ = weight of value xᵢ
Σ(wᵢ × xᵢ) = sum of weighted values
Σ(wᵢ) = sum of weights

Weighted mean gives different importance to different values. Useful for grades, ratings, and portfolio calculations.

Number of values must equal number of weights. Weights should be non-negative numbers.

What is Weighted Mean?

Weighted mean is an average where each data point contributes differently based on its weight. Heavier weights give more influence to certain values.

Unequal Importance

Used when some values are more important than others.

Grade Calculations

Commonly used for calculating course grades with credit hours.

Weighted Sum

Sum of value-weight products divided by sum of weights.

Normalized Weights

Weights can be normalized to sum to 1 for percentage-based weighting.

💡 Example: Values: 90, 85, 95. Weights: 3, 4, 3. W = (270 + 340 + 285) / 10 = 89.5.

Applications

Education Finance Statistics Data Analysis Ratings

Frequently Asked Questions

What is weighted mean?
Weighted mean is an average where each value has a different weight or importance. Formula: W = Σ(wᵢ × xᵢ) / Σ(wᵢ). Weights reflect the relative importance of each value.
When should I use weighted mean?
Use weighted mean when different data points have different importance. Examples: course grades with different credit hours, survey responses with different sample sizes, portfolio returns with different allocations.
Can weights be negative?
Weights are typically non-negative, representing importance or proportion. Negative weights would represent negative importance, which is rarely meaningful in practice.
What is the difference between weighted mean and arithmetic mean?
Arithmetic mean gives equal weight to all values. Weighted mean gives different weights based on importance. When all weights are equal, weighted mean equals arithmetic mean.

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