Charging Session Outliers (Z-Score)
Problem
**[Asked at Tesla]**
A charging session is an outlier if its `kwh_delivered` deviates from the
station's average by more than 1.5 standard deviations.
Return outlier sessions: `id`, `station`, `kwh_delivered`, `z_score`
(absolute value, rounded to 2 dp), ordered by z_score descending.
Tables
Example rows — the live problem includes the full dataset.
charging_sessions
| id | station | kwh_delivered |
|---|
Expected output
Your answer should return 2 rows with the columns id, station, kwh_delivered, z_score.
Starter code (SQL)
SELECT *
FROM charging_sessions;Solve this SQL question free
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Solution & explanation
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