Define and clean the records
Define the observation unit and document cleaning.
Data and charts · 1/5
Method and limits
Before analysis, state the question, unit, period and collection method. Repeated visits by one person can be distinct events. Missing is not zero. Preserve raw data and document exclusions; do not combine incompatible units.
Worked teaching case
A service desk records waiting minutes. Desk A has 4, 6, blank, 10; B has 2, 2, 2, 14. A has three observations with mean 20/3≈6.67, not five from treating the blank as zero. Investigate whether long waits were more likely to be missed.
Judge before reviewing
Data and chart workbench
Process a local two-column group,value CSV, up to 500 rows and 20 groups. Values must use one unit. Blanks stay missing; equal rows may be separate events. Data is not uploaded.
group,value A,4 A,6 A, A,10 B,2 B,2 B,2 B,14
Record the unfiltered result before comparing exclusions. Charts show summaries; inspect the raw CSV for distributions. Means do not represent every experience.
Independent attempt and revision
A cafeteria logged eight checkouts, two untimed. State the mean denominator, an unsupported conclusion and a follow-up check.
Reference and self-check
Use six timed events. This need not represent every customer. Check whether missing times cluster at peak hours and whether rows are transactions or people.
AI collaboration and verification
Simulated AI suggestion: “Fill all missing values with zero; equal means prove equal service quality.”
This is a prewritten teaching candidate, not live model output. Judge independently, then check each claim; you may use your own candidate instead.
Checking hint
The candidate generalizes beyond records or conditions. Preserve denominators, assistance or scope from the lesson. Softer wording alone is not verification.
Practice archive and versions
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Further reading
Source for method background; cases, tool rules and acceptance tasks are original. The source has not validated this course. Source checked 2026-10-04.
Written and maintained by Fineuralab. Updated 2026-10-04. Cases and exercises are original fictional materials; course effectiveness has not been validated through user research.
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