Technical practice
How would you turn a large, unstructured dataset into actionable recommendations?
What to coverSuggested preparation: Explain how you would define the business question, assess data quality, prepare the data and select an analytical approach. Describe how you would check that the resulting insights support a useful recommendation rather than merely a predictive score.
When would you choose an SVM, LSTM or transformer for a text analytics problem?
What to coverSuggested preparation: Compare their suitability for the task and available data, including trade-offs in complexity and computational cost. Explain how you would establish a baseline and test whether a more complex model improves results.
How would you design a rigorous framework for evaluating a model?
What to coverSuggested preparation: Discuss appropriate data splits, metrics tied to the business objective, and checks for leakage or performance differences across relevant data slices. Explain how you would use the results to guide iteration on accuracy and reliability.
How would you decide whether to fine-tune an open-source large language model?
What to coverSuggested preparation: Compare fine-tuning with prompting for a defined use case, considering available examples, evaluation results and implementation effort. Explain how you would test whether fine-tuning improves the behavior that matters for that use case.
How would you improve an LLM's behavior through prompt engineering?
What to coverSuggested preparation: Describe a controlled way to vary instructions and examples while keeping evaluation cases consistent. Address how you would inspect failures and avoid treating a few convincing responses as evidence of reliable performance.
How do embeddings, a vector database and LangChain fit into a text-retrieval solution?
What to coverSuggested preparation: Explain the distinct roles of text embeddings, similarity search and application orchestration without assuming a particular architecture is required. Discuss how you would evaluate whether retrieved material is relevant and improves the final answer.
What would you check before deploying a model to production?
What to coverSuggested preparation: Cover validation against the intended use, reproducible inputs and outputs, and how you would detect a decline in performance after deployment. Explain the trade-off between improving a model further and releasing a sufficiently tested version.
How would you use Python, NumPy, SciPy and scikit-learn in an analysis workflow?
What to coverSuggested preparation: Give concrete examples of array-based preparation, statistical analysis and model fitting or evaluation that fit each library's purpose. Explain how you would make the work reproducible and verify intermediate results.
How would you protect data integrity, security and compliance in a data science project?
What to coverSuggested preparation: Discuss checks on data provenance and quality, appropriate access controls, and documenting how data is used. Avoid assuming a particular regulation; explain how you would establish which obligations apply before setting governance rules.
How would you assess a new method for improving an existing AI model?
What to coverSuggested preparation: Define the observed limitation, a measurable hypothesis and a comparison against the current approach. Discuss how you would weigh gains in performance against complexity and share useful findings with the team.
Behavioural practice
Tell me about a time you explained a technical finding to a client or stakeholder.
What to coverSuggested preparation: Use a real situation, the audience's decision, and the actions you took to make the finding understandable. State the result, including how you handled uncertainty or questions.
Describe a time an experiment or model underperformed and you iterated on it.
What to coverSuggested preparation: Give the initial goal and evidence that the approach fell short, then explain how you diagnosed the issue and chose the next test. Report the outcome, including what you learned if performance did not improve.
Tell me about a time you addressed a data-quality, security or governance concern.
What to coverSuggested preparation: Describe the concern, your responsibility and the steps you took with relevant colleagues. Explain the result without implying that every issue could be resolved by model changes alone.
Describe a time you worked across teams to integrate a data-driven solution.
What to coverSuggested preparation: Set out the teams' differing needs, what you did to coordinate the work and how decisions were made. Explain the outcome and your specific contribution.
Tell me about a time you shared a useful data science finding with your team.
What to coverSuggested preparation: Identify the method or insight, why it was relevant and how you evaluated it before sharing it. Describe what the team did with the information, if anything, and what you learned.