Amazon Web Services AWS Certified Machine Learning Engineer - Associate MLA-C01 Exam Dumps: Updated Questions & Answers (May 2026)

Step 1: Create a feature group.

Step 2: Ingest the records.

Step 3: Access the store to build datasets for training.

Step 1: Create a Feature Group

Why? A feature group is the foundational unit in SageMaker Feature Store, where features are defined, stored, and organized. Creating a feature group specifies the schema (name, data type) for the features and the primary keys for data identification.

How? Use the SageMaker Python SDK or AWS CLI to define the feature group by specifying its name, schema, and S3 storage location for offline access.

Step 2: Ingest the Records

Why? After creating the feature group, the raw data must be ingested into the Feature Store. This step populates the feature group with data, making it available for both real-time and offline use.

How? Use the SageMaker SDK or AWS CLI to batch-ingest historical data or stream new records into the feature group. Ensure the records conform to the feature group schema.

Step 3: Access the Store to Build Datasets for Training

Why? Once the features are stored, they can be accessed to create training datasets. These datasets combine relevant features into a single format for machine learning model training.

How? Use the SageMaker Python SDK to query the offline store or retrieve real-time features using the online store API. The offline store is typically used for batch training, while the online store is used for inference.

Order Summary:

Create a feature group.

Ingest the records.

Access the store to build datasets for training.

This process ensures the features are properly managed, ingested, and accessible for model training using Amazon SageMaker Feature Store.

Logistic regression requires numeric input features and is sensitive to how categorical variables are encoded. AWS feature engineering best practices recommend one-hot encoding for low-cardinality categorical variables with no inherent order and ordinal encoding for categorical variables with a meaningful order.

The location feature has only three distinct values and no ordinal relationship, making one-hot encoding the most appropriate method. This prevents the model from inferring a false numerical relationship between locations.

The job_seniority_level feature typically has an inherent order (for example: junior, mid-level, senior, lead). Even with more than 10 categories, ordinal encoding preserves this natural hierarchy while keeping the feature dimensionality manageable.

Tokenization is used for unstructured text, not structured categorical variables. Standard scaling applies only to continuous numeric features and is not suitable for categorical string variables.

AWS documentation explicitly highlights using one-hot encoding for nominal features and ordinal encoding for ordered categorical features when preparing data for linear models such as logistic regression.

Therefore, Option B is the correct and AWS-aligned solution.

Amazon EMR clusters consist of primary, core, and task nodes, each with a distinct role. The primary node manages the cluster, core nodes store data and run tasks, and task nodes only run tasks without storing data. AWS documentation recommends using task nodes for scaling compute capacity when workloads are compute-intensive, such as data ingestion and transformation pipelines.

To reduce processing time cost-effectively, AWS strongly advises using Spot Instances for task nodes. Spot Instances provide the same compute capacity as On-Demand Instances but at a significantly reduced cost, often up to 90% lower. Because task nodes do not store HDFS data, they can be safely interrupted without risking data loss.

Increasing the number of primary nodes is not supported by EMR and would not improve performance. Increasing core nodes affects both storage and compute and is more expensive, especially when using On-Demand Instances. Option D is therefore the least cost-effective.

AWS EMR best practices explicitly state that scaling out with Spot task nodes is the preferred way to improve performance for transient, parallel workloads such as ETL, ingestion, and feature preparation.

Therefore, Option C is the most cost-effective and AWS-recommended solution.

Change the number of samples used in each iteration of training

Correct selection:

Change the batch size

Why:

Increasing the batch size reduces the number of iterations per epoch, which can significantly shorten training time while maintaining model quality when tuned appropriately. AWS explicitly recommends batch size tuning as a primary performance optimization.

Increase the number of instances used during training

Correct selection:

Use the SageMaker AI distributed data parallelism (SMDDP) library

Why:

SMDDP is designed to efficiently distribute training data across multiple GPU instances with optimized gradient synchronization. This accelerates training without affecting model convergence or accuracy, unlike naive scaling approaches.

Stop training before the maximum number of epochs are reached if performance is sufficient and not improving

Correct selection:

Use early stopping on the training job

Why:

Early stopping automatically terminates training when validation metrics stop improving. AWS recommends this to reduce wasted compute time while preserving optimal model performance.

Option A is correct because AWS Glue provides the lowest-overhead managed pattern for this scenario: use a crawler to keep the AWS Glue Data Catalog updated for the S3 dataset, then use AWS Glue Data Quality to evaluate rules against that cataloged data. AWS documentation states that crawlers can automatically discover and catalog new or updated S3 data sources, reducing manual metadata management overhead. AWS Glue Data Quality is also documented as a managed, serverless capability for measuring and monitoring data quality.

This option is especially strong because the dataset is already in Amazon S3 and partitioned by date, and the requirement is simply to automatically check quality before the data is sent to QuickSight. AWS Glue Data Quality supports the Data Catalog as an entry point, and AWS documentation notes that this approach is intended for datasets that are already cataloged and for ongoing governance-style quality evaluation. The docs also show that scheduling is supported for Data Catalog-based quality checks. That means the company can run the crawler monthly, then evaluate a ruleset against the cataloged table without needing custom ETL code.

The other options add more operational work. Option B requires a custom PySpark job and custom functions, which is more maintenance-heavy than using catalog-based quality rules directly. Option C depends on bespoke Lambda scripts. Option D does not use the right service for data quality validation. Because the question asks for the least operational overhead, the most AWS-aligned answer is A: monthly Glue crawler plus Glue Data Quality rules.

The problem described is a patient segmentation use case, which is a classic example of unsupervised learning. The objective is to group patients with similar characteristics without predefined labels. AWS documentation clearly states that Amazon SageMaker k-means is designed specifically for clustering and segmentation tasks.

The SageMaker k-means algorithm groups data points into clusters based on feature similarity and requires the user to define the number of clusters using the k hyperparameter. This directly satisfies the requirement to “determine the number of groups by using hyperparameters.” AWS recommends k-means for applications such as customer segmentation, risk grouping, and pattern discovery in healthcare data.

Option A (XGBoost) is a supervised learning algorithm used for classification and regression. The max_depth hyperparameter controls tree complexity, not the number of groups, making it unsuitable for this task.

Option C (DeepAR) is a time-series forecasting algorithm optimized for predicting future values, not clustering patients.

Option D (Random Cut Forest) is an anomaly detection algorithm. While useful for identifying outliers or unusual patient behavior, it does not perform clustering or group segmentation.

AWS SageMaker documentation explicitly identifies k-means as the correct choice when the goal is to partition data into a predefined number of clusters using a tunable hyperparameter.

Therefore, Option B is the correct and AWS-verified answer.

AWS Bedrock Knowledge Bases support multiple chunking strategies to optimize retrieval quality. Hierarchical chunking is specifically designed for structured documents such as PDFs with headings, sections, and subsections.

Hierarchical chunking allows fine-grained retrieval at the subsection level while automatically preserving parent section context. This ensures that when a small portion is retrieved, the surrounding section is also provided to the foundation model for better understanding.

Fixed-size and maximum-token chunking can split content arbitrarily, breaking semantic and structural boundaries. Semantic chunking focuses on meaning but does not guarantee structured context preservation without additional logic.

AWS documentation highlights hierarchical chunking as the preferred strategy when documents are structured and contextual integrity is required.

Therefore, Option A is the correct and AWS-aligned solution.

The primary requirement is dimensionality reduction on high-dimensional structured data to uncover hidden patterns. Principal Component Analysis (PCA) is a linear dimensionality reduction technique specifically designed for this purpose and is available as a built-in algorithm in Amazon SageMaker.

PCA transforms the original features into a smaller set of orthogonal components that preserve the maximum possible variance. This makes PCA ideal for large tabular datasets such as census data, where hundreds of correlated variables are common.

t-SNE (Option B) is mainly used for visualization in very low dimensions (2D or 3D) and does not scale well for large datasets or production analysis. k-means (Option C) is a clustering algorithm, not a dimensionality reduction method. Random Cut Forest (Option D) is used for anomaly detection.

Therefore, PCA is the correct and AWS-recommended solution.

The correct answer is A. Enable CloudTrail log file integrity validation.

AWS CloudTrail provides the ability to record API calls made to AWS services and delivers log files to an Amazon S3 bucket. For organizations that need to ensure the authenticity and integrity of these log files, AWS recommends enabling log file integrity validation. This feature applies a hash function to each log file and stores the hash separately, allowing you to verify that the logs have not been altered, deleted, or tampered with after delivery.

Enabling log file integrity validation is critical in ML operations when auditing model training pipelines, production inference calls, or system access patterns across accounts. It ensures that security-sensitive API activity is accurately recorded and verifiable. In multi-account environments managed by AWS Organizations, this validation provides an extra layer of trust when logs are consolidated from multiple accounts.

Option B, creating a multi-Region trail, ensures that API activity across regions is logged but does not inherently guarantee the integrity of logs. Option C, creating an organization trail, centralizes logging for all accounts, which is valuable for governance, but again does not automatically provide verification of log integrity. Option D, enabling CloudWatch Logs delivery, allows real-time monitoring and alerting but does not address the verification of historical log files.

By enabling log file integrity validation, organizations can cryptographically verify each log file, detect unauthorized changes, and meet compliance requirements for secure ML monitoring and auditing. This aligns with AWS best practices for ML solution monitoring, maintenance, and security, ensuring reliable tracking of model operations and API usage across distributed ML systems.

The key requirements in this scenario are variable traffic patterns and cost efficiency. The workload has unpredictable spikes during evenings and weekends, followed by long periods of low or no usage. According to AWS Machine Learning documentation, Amazon SageMaker Serverless Inference is specifically designed for such use cases.

SageMaker Serverless Inference automatically provisions, scales, and shuts down compute resources based on incoming inference requests. Customers are billed only for the compute time used during inference, not for idle resources. This makes it highly cost-effective for workloads with intermittent or spiky traffic, such as real-time chat moderation in gaming environments.

Option A is incorrect because batch transform jobs are intended for offline, large-scale inference and require fixed capacity during job execution. They are not suitable for real-time NLP moderation.

Option C is also incorrect because reserving an EC2 GPU instance incurs continuous costs regardless of utilization. This would be inefficient given the long idle periods described in the scenario.

Option D, SageMaker Asynchronous Inference, is designed for workloads with long processing times or large payloads and still requires endpoint provisioning. While it can handle traffic spikes, it does not scale down to zero in the same cost-efficient manner as Serverless Inference.

Therefore, Amazon SageMaker Serverless Inference is the most cost-effective and operationally efficient solution for deploying an NLP moderation model with highly variable usage patterns.