An average needs its count

A mean of means can change the question

East has two amounts, 10 and 30, so its average is 20. West has one amount, 100. Averaging the two displayed means gives 60, treating the two regions equally. Averaging all three records gives 140 / 3, about 46.67. Both are calculations, but they answer different questions.

Carry totals and counts

For a record-weighted combined average, add the underlying totals and divide by the underlying counts. Do not add or average rounded display values. The reporting workshop recomputes margin averages from source records so a small group does not receive the weight of a large group.

Zero belongs in the denominator

A recorded zero is an observation. A group with amounts 0 and 20 has an average of 10. A group with no numeric records has no average; showing a dash makes that absence visible. Replacing every missing group with zero would invent observations.

When reporting counts, state what is counted: all rows, numeric values or nonblank labels. In these workshops every accepted source row has a numeric amount, so the record count includes zero and refunds.

Try the idea

• Practice a workload-weighted mean →
• Build the operational review →
• Try sum, count and average →
• AVERAGE function examples →

References

• Microsoft: AVERAGE ↗

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