AI0-001 Practice Test 4 — 10 Questions

Question 1

A large e-commerce company uses a recommendation system based on collaborative filtering. The system uses a matrix factorization model that is trained nightly on the entire user-item interaction history. Recently, the company launched a flash sale with thousands of new products. Users are reporting that the recommendations are not showing the new products, even for users who have purchased them during the sale. The data engineering team notices that the new products have very few interactions in the training data. The model's loss on the validation set has increased, and the recall@10 metric has dropped from 0.45 to 0.32. The team needs to improve the recommendation of new items without retraining the entire model from scratch every hour. Which approach should the team take?

Accepted Answer

Use a hybrid model that combines collaborative filtering with content-based features from product metadata. Option A is correct because a hybrid model that combines collaborative filtering with content-based features (e.g., product metadata like category, price, or description) can recommend new products even with zero or very few user interactions. The content-based component leverages item attributes to compute similarity between new and existing items, enabling the system to surface new products without requiring extensive interaction history. This approach addresses the cold-start problem for new items while preserving the collaborative filtering signal for established items, and it does not require retraining the entire model from scratch every hour.

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Retrain the model every hour to incorporate new interactions quickly

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Remove the new products from the recommendation pool until they accumulate enough interactions

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Increase the number of latent factors in the matrix factorization model

Question 2

A machine learning team is deploying a model that predicts customer churn. They notice that the model's predictions are highly sensitive to small changes in input features, leading to inconsistent outputs. Which technique should the team apply to improve model stability?

Accepted Answer

Regularization. Regularization (Option C) is the correct technique because it adds a penalty term to the loss function (e.g., L1 or L2 regularization), which constrains the model's weights. This reduces variance and prevents overfitting to noise in the training data, directly addressing the high sensitivity to small input changes (brittleness). By shrinking coefficients, regularization forces the model to learn more general patterns, improving stability and consistency in predictions.

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Increase learning rate

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Feature scaling

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Cross-validation

Question 3

A data scientist is training a convolutional neural network (CNN) for object detection. The training loss decreases rapidly but then plateaus at a high value, and the validation loss starts increasing. Which action should the scientist take to improve the model?

Accepted Answer

Reduce the model complexity. The training loss decreasing rapidly then plateauing at a high value while validation loss increases is classic overfitting. Reducing model complexity (Option C) directly addresses overfitting by decreasing the number of parameters or applying regularization (e.g., dropout, L2), which forces the network to learn more generalizable features rather than memorizing noise in the training data.

Answer

Increase the learning rate

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Increase the number of epochs

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Add more convolutional layers

Question 4

A data scientist is training a multi-class classifier with 10 classes. The training log shows the above output for the first two epochs. What is the most likely cause?

Accepted Answer

The learning rate is set to zero. When the learning rate is set to zero, the optimizer makes no updates to the model weights regardless of the computed gradients. The training loss remains constant across epochs because the parameters never change, which matches the log showing identical loss values for both epochs. This is a common debugging scenario where a misconfigured learning rate prevents any learning from occurring.

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Batch normalization is disabled

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The dataset is imbalanced

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The model is overfitting

Question 5

A data scientist is preparing a dataset for training a classification model. The dataset contains 10,000 records with a binary target variable where 9,500 belong to class A and 500 belong to class B. Which technique should the scientist use to address the class imbalance?

Accepted Answer

SMOTE (Synthetic Minority Oversampling Technique). SMOTE is the correct technique because it generates synthetic samples for the minority class (class B) by interpolating between existing minority instances, effectively balancing the dataset without losing information. This approach avoids the overfitting risk of simple oversampling and the information loss of undersampling, making it ideal for a 19:1 imbalance ratio.

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Random undersampling of class A

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Adding Gaussian noise to class B

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Principal Component Analysis (PCA)

Question 6

An engineer is building a regression model to predict housing prices. The dataset includes features such as square footage, number of bedrooms, and year built. The engineer notices that the square footage values range from 500 to 10,000, while the number of bedrooms ranges from 1 to 5. Which preprocessing step is most critical before training a gradient descent-based model?

Accepted Answer

Normalize or standardize the features. Gradient descent-based models are sensitive to the scale of input features because they update weights proportionally to the gradient, which is influenced by feature magnitudes. With square footage ranging 500–10,000 and bedrooms 1–5, the larger feature will dominate the gradient, causing slow or unstable convergence. Normalizing or standardizing (e.g., Z-score or min-max scaling) ensures all features contribute equally, leading to faster and more reliable training.

Answer

Use k-fold cross-validation

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Apply log transformation to all features

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One-hot encode the features

Question 7

Which TWO techniques are commonly used for feature selection in machine learning? (Choose 2)

Accepted Answer

L1 regularization (Lasso). L1 regularization (Lasso) is correct because it adds a penalty equal to the absolute value of the magnitude of coefficients, which can shrink some coefficients exactly to zero, effectively performing feature selection by removing irrelevant features from the model. This makes it a built-in feature selection technique within the training process.

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Principal Component Analysis (PCA)

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SMOTE

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Dropout

Question 8

A company uses an AI system to recommend products. The recommendation accuracy is high, but users complain about lack of diversity. Which strategy should the team adopt to improve diversity without significantly sacrificing accuracy?

Accepted Answer

Modify the loss function to include a term that penalizes overly similar recommendations.. Option D is correct because modifying the loss function to include a diversity penalty directly addresses the lack of recommendation diversity at the algorithmic level. By adding a regularization term that penalizes overly similar recommendations, the model learns to balance accuracy with variety, ensuring that the output set remains diverse without a significant drop in relevance. This approach is a standard technique in recommendation systems, often implemented via Determinantal Point Processes (DPPs) or diversity-aware loss functions.

Answer

Randomly replace some recommendations with popular items.

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Use only popularity-based recommendations.

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Increase the number of recommendations and use collaborative filtering.

Question 9

A company deployed a chatbot using a pre-trained language model. Users report that the chatbot provides incorrect answers to domain-specific questions. Which approach should the AI team prioritize to improve accuracy without retraining the entire model?

Accepted Answer

Fine-tune the model on a curated dataset of domain-specific conversations.. Fine-tuning on a curated domain-specific dataset is the most efficient way to improve accuracy for specialized queries without retraining the entire model. It adjusts the model's weights using a smaller, targeted dataset, preserving general language understanding while adapting to domain terminology and context.

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Increase the temperature parameter to reduce randomness.

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Collect more general training data and retrain the model from scratch.

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Roll back to a previous version of the model that was more accurate.

Question 10

An organization is implementing an AI-powered chatbot for customer service. The chatbot must comply with GDPR and handle data subject access requests (DSARs). Which design approach best ensures compliance?

Accepted Answer

Implement an audit trail that logs interactions with a unique user identifier, and provide a mechanism to delete logs upon user request.. Option C is correct because GDPR requires that personal data be stored only as long as necessary and that data subjects have the right to erasure. By logging interactions with a unique user identifier and providing a deletion mechanism, the chatbot can fulfill DSARs while maintaining an audit trail for compliance monitoring. This approach balances operational needs with regulatory obligations.

Answer

Minimize data collection by not logging any user interactions.

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Anonymize all user data before logging interactions.

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Encrypt all chat logs and store them indefinitely for audit purposes.