Pass the Amazon Web Services AWS Certified AI Practitioner AIF-C01 Questions and answers with CertsForce

Comprehensive and Detailed Explanation From Exact AWS AI documents:

Feature engineering focuses on:

Creating new features

Selecting the most relevant existing features

Improving model signal and accuracy

AWS ML best practices identify feature engineering as a key driver of predictive performance.

Why the other options are incorrect:

Visualization (A) helps understanding, not feature creation.

Hyperparameter tuning (B) optimizes models, not features.

Data collection (D) expands datasets but does not engineer features.

AWS AI document references:

Feature Engineering Best Practices

Improving Model Accuracy on AWS

ML Model Development Lifecycle

Step 1: Define the business objective.

Step 2: Process the data.

Step 3: Develop and train the model.

Step 4: Deploy the model.

The correct order represents the machine learning lifecycle as defined by AWS in the Amazon SageMaker documentation and AWS Certified Machine Learning Specialty Study Guide. The lifecycle describes the sequence of tasks required to build, train, and deploy a custom ML model effectively.

From AWS documentation:

"The machine learning process begins with defining the business problem, followed by collecting and processing data, developing and training models, and finally deploying them into production for inference."

Step 1 – Define the business objective:

This step involves clearly identifying the business problem to be solved and determining the measurable outcomes expected from the ML model. This ensures alignment between business goals and ML outputs.

Step 2 – Process the data:

Data is collected, cleaned, transformed, and prepared for training. This includes handling missing values, normalizing data, and performing feature engineering — a crucial phase that influences model performance.

Step 3 – Develop and train the model:

The model is built and trained on the processed data using algorithms appropriate to the problem (e.g., regression, classification, clustering). Hyperparameters are tuned to optimize model accuracy.

Step 4 – Deploy the model:

Once validated, the model is deployed to a production environment (e.g., Amazon SageMaker endpoint) to make predictions on new data. Continuous monitoring and retraining ensure the model remains effective.

Referenced AWS AI/ML Documents and Study Guides:

Amazon SageMaker Developer Guide – Machine Learning Lifecycle

AWS Certified Machine Learning Specialty Study Guide – Model Development Lifecycle

AWS ML Best Practices Whitepaper – End-to-End ML Workflow

To determine customer sentiments based on written customer reviews, the company can use Amazon Comprehend and Amazon Bedrock.

Amazon Comprehend:

A natural language processing (NLP) service that uses machine learning to uncover insights and relationships in text.

Can analyze customer reviews to detect sentiments (positive, negative, neutral, or mixed) automatically.

Amazon Bedrock:

Provides access to foundational models (FMs) from multiple AI companies for tasks such as text generation, summarization, and sentiment analysis.

The company can use a pre-trained sentiment analysis model available on Amazon Bedrock for processing customer reviews.

Why Other Options are Incorrect:

A. Amazon Lex: Used for building conversational interfaces like chatbots, not for sentiment analysis.

C. Amazon Polly: Converts text to speech; it doesn't analyze sentiment.

E. Amazon Rekognition: Analyzes images and videos, not text.

The company needs to automatically group similar customers and products based on their characteristics, which is a clustering task. Unsupervised learning is the ML strategy for grouping data without labeled outcomes, making it ideal for this requirement.

Exact Extract from AWS AI Documents:

From the AWS AI Practitioner Learning Path:

"Unsupervised learning is used to identify patterns or groupings in data without labeled outcomes. Common applications include clustering, such as grouping similar customers or products based on their characteristics, using algorithms like K-means or hierarchical clustering."

(Source: AWS AI Practitioner Learning Path, Module on Machine Learning Strategies)

Detailed Explanation:

Option A: Unsupervised learningThis is the correct answer. Unsupervised learning, specifically clustering, is designed to group similar entities (e.g., customers or products) based on their characteristics without requiring labeled data.

Option B: Supervised learningSupervised learning requires labeled data to train a model for prediction or classification, which is not applicable here since the task involves grouping without predefined labels.

Option C: Reinforcement learningReinforcement learning involves training an agent to make decisions through rewards and penalties, not for grouping data. This option is irrelevant.

Option D: Semi-supervised learningSemi-supervised learning uses a mix of labeled and unlabeled data, but the task here does not involve any labeled data, making unsupervised learning more appropriate.

The best solution is Amazon Bedrock Knowledge Bases, which allows for the seamless integration of structured and unstructured internal documents—such as PDFs, CSVs, and extracted image text—into a retrieval-augmented generation (RAG) pipeline. According to AWS documentation, Bedrock Knowledge Bases offer a no-code or low-code setup to link your enterprise data with foundation models for context-aware responses, without needing to fine-tune or retrain models. The system indexes documents in an Amazon S3 bucket, creates embeddings, and stores them in a vector store. At inference time, the model retrieves relevant context and incorporates it into its response. This approach provides dynamic and up-to-date responses while maintaining data privacy, with minimal operational overhead. Unlike fine-tuning or building a model from scratch in SageMaker, which requires considerable compute resources and model management, Bedrock Knowledge Bases are serverless and easy to configure. It is designed exactly for internal knowledge AI assistants.

Referenced AWS AI/ML Documents and Study Guides:

Amazon Bedrock Developer Guide – Knowledge Bases

AWS Generative AI Best Practices – RAG Patterns for Enterprise Search

AWS documentation recommends exposing deployed machine learning models through secure, managed API endpoints to provide controlled and scalable access for external consumers. Creating a secure API endpoint allows customers to invoke the model using standard HTTPS requests while maintaining strict security boundaries.

AWS services such as Amazon SageMaker support deploying models behind managed endpoints that integrate with AWS security features, including authentication, authorization, encryption in transit, throttling, and monitoring. By using an API-based approach, the company can ensure that external customers interact with the model without gaining direct access to the underlying infrastructure or credentials.

The other options introduce significant security risks. Sharing credentials directly violates AWS security best practices and could lead to unauthorized access. Custom authentication scripts in customer applications are difficult to standardize and maintain. Embedding the model directly into customer applications removes centralized control and makes updates and security management impractical.

AWS positions secure API endpoints as the preferred mechanism for exposing ML inference capabilities to external clients, making this the correct solution.

When you have a labeled dataset and need to scale a generative AI solution for more complex or diverse product categories, fine-tuning the foundation model with your dataset is the best approach for consistent, accurate tagging.

D is correct:

“Fine-tuning a foundation model with your labeled data allows the model to generalize to new categories and improve tagging accuracy for your inventory.”

(Reference: Amazon Bedrock Fine-Tuning, AWS Generative AI)

A (zero-shot) and B (prompt templates) do not leverage the labeled data or scale as accurately.

C (continued pre-training) uses unlabeled data, not labeled.

The requirement is to identify an AWS database service that supports the storage and querying of embeddings (from a generative AI model) as vectors. Embeddings are typically high-dimensional numerical representations of data (e.g., text, images) used in AI applications like conversational search. The database must support vector storage and efficient vector similarity searches. Let’s evaluate each option:

A. Amazon Athena: Amazon Athena is a serverless query service for analyzing data in Amazon S3 using SQL. It is designed for ad-hoc querying of structured data but does not natively support vector storage or vector similarity searches, making it unsuitable for this use case.

B. Amazon Aurora PostgreSQL: Amazon Aurora PostgreSQL is a fully managed relational database compatible with PostgreSQL. With the pgvector extension (available in PostgreSQL and supported by Aurora PostgreSQL), it can store and query vector embeddings efficiently. The pgvector extension enables vector similarity searches (e.g., using cosine similarity or Euclidean distance), which is critical for conversational search applications using embeddings from generative AI models.

C. Amazon Redshift: Amazon Redshift is a data warehousing service optimized for analytical queries on large datasets. While it supports machine learning features and can store numerical data, it does not have native support for vector embeddings or vector similarity searches as of May 17, 2025, making it less suitable for this use case.

D. Amazon EMR: Amazon EMR is a managed big data platform for processing large-scale data using frameworks like Apache Hadoop and Spark. It is not a database service and is not designed for storing or querying vector embeddings in the context of a conversational search application.

Exact Extract Reference: According to the AWS documentation, “Amazon Aurora PostgreSQL-Compatible Edition supports the pgvector extension, which enables efficient storage and similarity searches for vector embeddings. This makes it suitable for AI/ML workloads such as natural language processing and recommendation systems that rely on vector data.” (Source: AWS Aurora Documentation - Using pgvector with Aurora PostgreSQL, https://docs.aws.amazon.com/AmazonRDS/latest/AuroraUserGuide/PostgreSQLpgvector.html). Additionally, the pgvector extension supports operations like nearest-neighbor searches, which are essential for querying embeddings in a conversational search system.

Amazon Aurora PostgreSQL with the pgvector extension directly meets the requirement for storing and querying embeddings as vectors, making B the correct answer.

Underfitting occurs when a machine learning model is too simple to capture the underlying patterns in the training data. AWS documentation explains that an underfit model performs poorly on both training and test datasets, which directly matches the scenario described.

In this case, the model shows low accuracy during training and evaluation, indicating that it has not learned sufficient relationships from the data. AWS identifies common causes of underfitting as insufficient model complexity, inadequate feature representation, overly aggressive regularization, or insufficient training time.

Underfitting is different from overfitting. Overfitting occurs when a model performs well on training data but poorly on test data, which is not the situation here. Hallucination applies to generative AI outputs, not supervised ML model accuracy. Cross-validation is a model evaluation technique, not a cause of poor performance.

AWS emphasizes the importance of diagnosing underfitting early in the model development lifecycle. Remedies include increasing model complexity, adding relevant features, reducing regularization, or selecting a more expressive algorithm. These steps allow the model to better learn from the data and improve accuracy across both training and test sets.

AWS machine learning best practices clearly associate low performance on both datasets with underfitting, making this the most likely cause of the problem described.