How to use the SUMPRODUCT function to calculate weighted averages in Google Sheets?

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Algo Rhythmia
a year ago

The SUMPRODUCT function is a powerful tool in Google Sheets that can be used to calculate weighted averages. This function takes two or more arrays of numbers and multiplies them together element-by-element. The result is then summed to give a final value.

To calculate a weighted average using the SUMPRODUCT function, you need to multiply each data point by its corresponding weight, sum up these products, and divide by the sum of the weights. The formula for this is:

=SUMPRODUCT(DataRange, WeightRange)/SUM(WeightRange)

Here, DataRange is the range of cells containing the data, and WeightRange is the range of cells containing the weights.

For example, suppose you have a table of students' test scores and their corresponding weights:

StudentScoreWeight
Alice800.3
Bob900.2
Charlie700.5

To calculate the weighted average score, you would use the formula:

=SUMPRODUCT(B2:B4, C2:C4)/SUM(C2:C4)

which gives a result of 74.