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Model Selection and Hyperparameter Tuning Questions

Covers the end to end process of choosing, training, evaluating, and optimizing machine learning models. Topics include selecting appropriate algorithm families for the task such as classification versus regression and linear versus non linear models, establishing training pipelines, and preparing data splits for training validation and testing. Explain model evaluation strategies including cross validation, stratification, and nested cross validation for unbiased hyperparameter selection, and use appropriate performance metrics. Describe hyperparameter types and their effects such as learning rate, batch size, regularization strength, tree depth, and kernel parameters. Compare and apply tuning methods including grid search, random search, Bayesian optimization, successive halving and bandit based approaches, and evolutionary or gradient based techniques. Discuss practical trade offs such as computational cost, search space design, overfitting versus underfitting, reproducibility, early stopping, and when to prefer simple heuristics or automated search. Include integration with model pipelines, logging and experiment tracking, and how to document and justify model selection and tuned hyperparameters.

MediumTechnical
0 practiced
Compare ROC AUC and PR AUC for imbalanced binary classification. Explain why PR AUC can be more informative for rare positive classes, how calibration impacts these metrics, and when to use precision at K or recall at fixed precision in business settings.
MediumTechnical
0 practiced
Compare regularization techniques across model families: L1 vs L2 for linear models, dropout and weight decay for neural networks, and tree regularization via max_depth or min_samples_leaf. For each, explain the mechanism, effect on sparsity or capacity, and situations where one is preferred over another.
MediumTechnical
0 practiced
As a senior data scientist you must convince product and engineering to reduce the number of tuning experiments due to a looming deadline. How would you prioritize which experiments to run, justify using heuristics or defaults over large-scale search, and communicate the expected risk and benefits to stakeholders?
MediumTechnical
0 practiced
Write Python code or a clear pseudocode snippet that runs a reproducible random search for scikit-learn estimators in parallel using joblib. The interface should accept a param distribution dict, n_iter, random_state, and n_jobs and return the best estimator and parameter set. Mention how to seed workers for reproducibility.
EasyTechnical
0 practiced
Describe what constitutes a meaningful baseline model for a new supervised ML problem and how baselines should be used before hyperparameter tuning. Include examples of simple heuristics and classic models you would run, and how to document baseline performance to justify more complex models.

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