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Define the question and the data contract
Define what you are counting before calculating an average.
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Define the question and the data contract
Define what you are counting before calculating an average.
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Source-based teaching example · Fictional data · Reviewed 2026-10-03. Microsoft Mark · locally synthesized. On a small screen, use fullscreen for diagram details or read the transcript.
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0:00 · What you will learn
Define what you are counting before calculating an average.
What appears on screen
Define what you are counting before calculating an average.
0:06 · The idea
State what one row represents, the units and which rows belong in the question. Missing is different from zero. Report excluded or unresolved rows separately.
What appears on screen
State what one row represents, the units and which rows belong in the question. Missing is different from zero. Report excluded or unresolved rows separately.
0:19 · One useful term
Denominator. The count or quantity you divide by when calculating a rate or average.
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The count or quantity you divide by when calculating a rate or average.
0:28 · A worked example
Two closed requests took thirty and forty-five minutes. An open request has no duration. The closed-request mean is 37.5 minutes, using two observations.
What appears on screen
Two closed requests took thirty and forty-five minutes. An open request has no duration. The closed-request mean is 37.5 minutes, using two observations.
0:43 · Your turn to think
Should the open request enter the completed-duration average as zero? Pause and decide before continuing.
What appears on screen
Should the open request enter the completed-duration average as zero? Pause the video if you need more time.
1:01 · Why this answer works
No. That changes the total you divide by and the meaning. The result describes only the two closed sample requests.
What appears on screen
No. That changes the total you divide by and the meaning. The result describes only the two closed sample requests.
1:12 · Check 1
Define the row unit and question.
What appears on screen
Define the row unit and question.
1:17 · Check 2
Separate open and invalid records.
What appears on screen
Separate open and invalid records.
1:22 · Check 3
Keep missing values different from zero.
What appears on screen
Keep missing values different from zero.
1:27 · Now try a different case
Open the lesson and try its different practice case. Use every check in the full task. Watching alone does not mark the lesson complete.
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Open the lesson Try the new case Check and revise The full task and its requirements are in the linked lesson.
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