Hays Data Scientist Interview Questions
The questions to prepare for a Hays Data Scientist interview. Questions from real interview reports rank first. Updated weekly.
Calculate average active salary by Hays department using a LEFT JOIN, GROUP BY, and NULL-safe aggregation.
HaysExplain how INNER JOIN and LEFT JOIN differ, and when to use each for matched-only versus all-left-row analysis.
HaysRank the top 3 completed rides per vehicle per day using joins, a CTE, and ROW_NUMBER.
WaymoCompute per-vehicle daily autonomous vs manual seconds from state-change logs using LEAD and conditional aggregation.
Explain how to choose between a simpler interpretable model and a more accurate black-box model.
HaysBuild a classifier for a highly imbalanced dataset and choose metrics, sampling, and thresholds that fit the minority class.
HaysExplain what statistical significance means and why it matters when interpreting experimental or analytical results.
HaysDesign a supply chain planning system for demand forecasting, inventory decisions, S&OP, and capacity planning.
HaysOutline the first checks to diagnose a sudden drop in a core product metric, starting with data quality, scope, and decomposition.
HaysIdentify the main pitfalls that can distort A/B test interpretation and explain how to guard against them.
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