You discover that a significant number of features in your dataset are highly correlated. Some features are critical for model performance, while others are redundant. What steps do you take to address this in the next few hours?
What a strong answer covers
Conducts correlation analysis to identify multicollinearity; assesses feature importance using techniques like recursive feature elimination or tree-based methods; determines which features to keep based on model impact; considers dimensionality reduction techniques; plans to retrain the model with selected features.
The follow-up you would get
You decide to remove several features. How do you ensure that the model’s performance does not degrade after this change?
Could you have answered that?
scenarioData Quality2 of 6
You receive an alert that a significant portion of the data used for training is corrupted. You have 30 minutes to decide how to proceed. What actions do you take?
What a strong answer covers
Identify the source of corruption and affected records; assess the impact on model performance; either remove problematic data or substitute with reliable data; communicate findings to the team; prepare for re-training if necessary.
The follow-up you would get
If the corrupted data is crucial for model accuracy, what alternatives do you consider?
Could you have answered that?
technicalStatistics3 of 6
You are working with a model that uses cross-validation to assess its performance. The mean score across folds is 0.75, with a standard deviation of 0.1. What does this suggest about the model's stability, and what actions should you consider?
What a strong answer covers
Indicates moderate variance in model performance across folds; considers methods to reduce variance such as increasing training data or simplifying the model; evaluates feature selection techniques; may experiment with different cross-validation strategies.
The follow-up you would get
How would you interpret the standard deviation in the context of model performance?
Could you have answered that?
technicalScaling4 of 6
You have a machine learning pipeline that successfully processes 1,000 records per minute but needs to scale to handle 10,000 records per minute. What considerations do you take into account to achieve this, and what changes do you implement first?
What a strong answer covers
Evaluates the current bottlenecks in data processing and model inference; considers parallel processing or batch processing techniques; assesses infrastructure for scalability options like cloud solutions; prioritises optimising code and algorithms before scaling hardware.
The follow-up you would get
How do you measure the impact of your changes on processing time and resource utilisation?
Could you have answered that?
technicalModel Evaluation5 of 6
You are evaluating a regression model that has a mean absolute error (MAE) of 5 and a mean squared error (MSE) of 50 on the validation set. What do these metrics suggest about the model's performance, and how do you interpret the difference between them?
What a strong answer covers
Recognises that the MAE indicates average error magnitude, while the MSE penalises larger errors more heavily; considers whether the distribution of errors is skewed; discusses potential outliers affecting MSE more than MAE; suggests investigating residual plots to identify patterns.
The follow-up you would get
How would you adjust your model if you find a significant number of outliers?
Could you have answered that?
ownershipHandling a failure6 of 6
Can you describe a time when you faced unexpected results from a model after deployment? How did you handle it?
What a strong answer covers
Names the specific unexpected results and their impact on business; discusses the process followed to investigate the root cause; details any changes made to the model or data; mentions communication with stakeholders and lessons learned; avoids blaming external factors.
The follow-up you would get
What indicators would you monitor to catch similar issues earlier?
Could you have answered that?
That is this set.
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