Weighted Variance Calculator
Calculate weighted variance where each value has a different weight representing frequency or reliability.
Enter Values and Weights
Examples:
Weighted Variance
150.000000
Weighted Std Dev
12.247449
Weighted Mean
30.000000
Coeff. of Variation
40.82%
Sum of Weights
9.0000
Comparison:
Weighted Variance:
150.000000
Unweighted Variance:
250.000000
Sum of Sq. Deviations:
1200.000000
What is Weighted Variance?
Weighted variance extends the concept of variance to accommodate values with different weights. The weights can represent frequency (how many times a value occurs) or reliability (how certain we are about each measurement). The calculation method differs based on the weight interpretation.
Formula
Weighted Var = Sum[wi * (xi - x_bar)^2] / (Sum[wi] - 1)
For frequency weights with Bessel's correction.