MLS-C01 Practice Exam — MLS-C01:Machine Learning - Specialty

AWS Certified Machine Learning - Specialty MLS-C01

Exam information

This exam was retired on March 31, 2026 and merged into AIP-C01.

Sample questions

MLS-C01 · Q1
Topic 1 Question #1 A large mobile network operating company is building a machine learning model to predict customers who are likely to unsubscribe from the service. The company plans to offer an incentive for these customers as the cost of churn is far greater than the cost of the incentive. The model produces the following confusion matrix after evaluating on a test dataset of 100 customers: " target="_blank" rel="nofollow noopener">https://www.examtopics.com/assets/media/exam-media/04145/0000200001.jpg"> Based on the model evaluation results, why is this a viable model for production?
  • A.
    The model is 86% accurate and the cost incurred by the company as a result of false negatives is less than the false positives.
  • B.
    The precision of the model is 86%, which is less than the accuracy of the model.
  • C.
    The model is 86% accurate and the cost incurred by the company as a result of false positives is less than the false negatives.
  • D.
    The precision of the model is 86%, which is greater than the accuracy of the model.

Answer: A

Confusion Matrix Analysis: True Positives (TP): 10 (Actual churn = Yes, Predicted churn = Yes) False Positives (FP): 10 (Actual churn = No, Predicted churn = Yes) True Negatives (TN): 76 (Actual churn = No, Predicted churn = No) False Negatives (FN): 4 (Actual churn = Yes, Predicted churn = No) Accuracy Calculation: Accuracy = TP+TNTotal=10+76100=0.86\frac{TP + TN}{Total} = \frac{10 + 76}{100} = 0.86 or 86%. Cost Justification: The problem states that the cost of churn (false negatives) is far greater than the cost of providing incentives (false positives). Since the false negatives (4) are low compared to true positives, the model effectively captures most churners, minimizing potential losses. The model's 86% accuracy and manageable false positives make it viable. Why Option A?: The key consideration is the cost impact. The model balances high accuracy with lower false negatives, which aligns with the company’s goal to prevent churn cost-effectively. Other Options: B: Precision is not mentioned as 86%; precision = TPTP+FP=1010+10=0.5\frac{TP}{TP + FP} = \frac{10}{10 + 10} = 0.5, or 50%. C: The focus is on false negatives, not false positives, because false negatives represent churners missed by the model. D: Precision is less than accuracy, so this is incorrect.<
MLS-C01 · Q2
Topic 1 Question #2 A Machine Learning Specialist is designing a system for improving sales for a company. The objective is to use the large amount of information the company has on users' behavior and product preferences to predict which products users would like based on the users' similarity to other users.What should the Specialist do to meet this objective?
  • A.
    Build a content-based filtering recommendation engine with Apache Spark ML on Amazon EMR
  • B.
    Build a collaborative filtering recommendation engine with Apache Spark ML on Amazon EMR.
  • C.
    Build a model-based filtering recommendation engine with Apache Spark ML on Amazon EMR
  • D.
    Build a combinative filtering recommendation engine with Apache Spark ML on Amazon EMR

Answer: B

Based on the given scenario, the best answer is: B. Build a collaborative filtering recommendation engine with Apache Spark ML on Amazon EMR. Here's why this is the most suitable approach: 1. Collaborative filtering is ideal for this use case because: - It predicts user preferences based on similarities between users. - It leverages the large amount of information the company has on users' behavior and product preferences. - It can recommend products that users might like based on the preferences of similar users. 2. Apache Spark ML on Amazon EMR is a good choice because: - Spark ML provides scalable machine learning libraries, including collaborative filtering algorithms. - Amazon EMR (Elastic MapReduce) allows for distributed processing of large datasets, which is crucial for handling the company's large amount of user information. - The combination of Spark ML and EMR can efficiently process and analyze big data for recommendation systems. 3. This approach aligns with AWS best practices for building recommendation systems at scale. To implement this solution: 1. Set up an Amazon EMR cluster with Apache Spark. 2. Use Spark ML's ALS (Alternating Least Squares) algorithm for collaborative filtering. 3. Process and prepare the user behavior and product preference data. 4. Train the model on historical data. 5. Use the trained model to generate product recommendations for users. Remember to follow AWS security best practices when implementing this solution, such as: - Use IAM roles for EMR to manage permissions securely. - Encrypt data at rest and in transit. - Implement proper network security for your EMR cluster. For the most up-to-date information on pricing, limits, and best practices for using Apache Spark ML on Amazon EMR, please refer to the official AWS documentation.
MLS-C01 · Q3
Topic 1 Question #3 A Mobile Network Operator is building an analytics platform to analyze and optimize a company's operations using Amazon Athena and Amazon S3.The source systems send data in .CSV format in real time. The Data Engineering team wants to transform the data to the Apache Parquet format before storing it on Amazon S3. Which solution takes the LEAST effort to implement?
  • A.
    Ingest .CSV data using Apache Kafka Streams on Amazon EC2 instances and use Kafka Connect S3 to serialize data as Parquet
  • B.
    Ingest .CSV data from Amazon Kinesis Data Streams and use Amazon Glue to convert data into Parquet.
  • C.
    Ingest .CSV data using Apache Spark Structured Streaming in an Amazon EMR cluster and use Apache Spark to convert data into Parquet.
  • D.
    Ingest .CSV data from Amazon Kinesis Data Streams and use Amazon Kinesis Data Firehose to convert data into Parquet.

Answer: D

Based on the given scenario, the solution that takes the LEAST effort to implement is: D. Ingest .CSV data from Amazon Kinesis Data Streams and use Amazon Kinesis Data Firehose to convert data into Parquet. [[1]](https:
MLS-C01 · Q4
Topic 1 Question #4 A city wants to monitor its air quality to address the consequences of air pollution. A Machine Learning Specialist needs to forecast the air quality in parts per million of contaminates for the next 2 days in the city. As this is a prototype, only daily data from the last year is available. Which model is MOST likely to provide the best results in Amazon SageMaker?
  • A.
    Use the Amazon SageMaker k-Nearest-Neighbors (kNN) algorithm on the single time series consisting of the full year of data with a predictor_type of regressor.
  • B.
    Use Amazon SageMaker Random Cut Forest (RCF) on the single time series consisting of the full year of data.
  • C.
    Use the Amazon SageMaker Linear Learner algorithm on the single time series consisting of the full year of data with a predictor_type of regressor.
  • D.
    Use the Amazon SageMaker Linear Learner algorithm on the single time series consisting of the full year of data with a predictor_type of classifier.

Answer: C

Based on the given scenario, the model most likely to provide the best results in Amazon SageMaker for forecasting air quality is: C. Use the Amazon SageMaker Linear Learner algorithm on the single time series consisting of the full year of data with a predictor_type of regressor. Here's why this is the most suitable approach: 1. Time Series Forecasting: The problem is a time series forecasting task, predicting air quality for the next 2 days based on historical daily data. 2. Linear Learner: This algorithm is suitable for both classification and regression problems. In this case, we're predicting a continuous value (parts per million of contaminants), which is a regression task. 3. Predictor Type: Setting the predictor_type to "regressor" is correct for this scenario, as we're predicting a numeric value rather than classifying into categories. 4. Data Compatibility: The Linear Learner algorithm can work well with the single time series of daily data for the past year. 5. Simplicity and Interpretability: For a prototype with limited data (one year of daily readings), a simpler model like Linear Learner may perform well and provide interpretable results. To implement this solution: 1. Prepare your data: Ensure your time series data is properly formatted and includes relevant features. 2. Configure the Linear Learner algorithm in SageMaker, setting the predictor_type to "regressor". [[1]](https:
MLS-C01 · Q5
Topic 1 Question #5 A Data Engineer needs to build a model using a dataset containing customer credit card informationHow can the Data Engineer ensure the data remains encrypted and the credit card information is secure?
  • A.
    Use a custom encryption algorithm to encrypt the data and store the data on an Amazon SageMaker instance in a VPC. Use the SageMaker DeepAR algorithm to randomize the credit card numbers.
  • B.
    Use an IAM policy to encrypt the data on the Amazon S3 bucket and Amazon Kinesis to automatically discard credit card numbers and insert fake credit card numbers.
  • C.
    Use an Amazon SageMaker launch configuration to encrypt the data once it is copied to the SageMaker instance in a VPC. Use the SageMaker principal component analysis (PCA) algorithm to reduce the length of the credit card numbers.
  • D.
    Use AWS KMS to encrypt the data on Amazon S3 and Amazon SageMaker, and redact the credit card numbers from the customer data with AWS Glue.

Answer: D

The correct answer is D. Use AWS KMS to encrypt the data on Amazon S3 and Amazon SageMaker, and redact the credit card numbers from the customer data with AWS Glue.
Key Reasons for Choosing Option D:
1. AWS KMS for Encryption
- AWS Key Management Service (KMS) is a managed service for creating and controlling encryption keys. It integrates natively with Amazon S3 (for server-side encryption of data at rest) and Amazon SageMaker (for encrypting data in transit and at rest, including model artifacts and training data). This ensures end-to-end encryption using industry-standard, AWS-vetted encryption methods, which is more secure than custom algorithms (as in Option A).
2. AWS Glue for Data Redaction
- AWS Glue is a fully managed ETL service that can be used to clean and transform data. Specifically, it can redact (remove or mask) sensitive fields like credit card numbers from the dataset during preprocessing. This ensures that sensitive information is not exposed during modeling, even if the dataset is used in SageMaker. Redaction is a critical part of data privacy and compliance (e.g., PCI-DSS for credit card data).
3. Security Best Practices
- Avoiding Custom Solutions: Option A uses a custom encryption algorithm, which is risky (custom algorithms may have vulnerabilities) and unnecessary when AWS provides secure, managed solutions like KMS.
- IAM Policy Limitations: Option B incorrectly uses IAM policies for encryption. IAM manages access control, not data encryption. Encryption requires services like KMS or S3 Server-Side Encryption (SSE).
- PCA Misuse: Option C suggests using PCA to "reduce the length of credit card numbers," which is invalid. PCA is a dimensionality reduction technique, not a data masking or redaction tool. Credit card numbers must be explicitly redacted or tokenized, not altered via PCA.
Implementation Steps:
1. Encrypt Data in Amazon S3:
- Enable S3 Server-Side Encryption (SSE) with KMS-managed keys (SSE-KMS) to encrypt credit card data at rest in S3.
2. Redact Sensitive Data with AWS Glue:
- Use Glue ETL jobs to process the dataset, identifying and removing credit card numbers from the data before it is used in SageMaker. This can be done using regex or built-in data masking functions.
3. Secure SageMaker Workflow:
- Configure SageMaker to use KMS keys for encrypting data during training and inference. Host SageMaker instances in a private VPC for network isolation.
4. Access Control:
- Use IAM roles to grant least-privilege access to S3, Glue, and SageMaker, ensuring only authorized users

FAQ

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This question bank includes 369 MLS-C01 practice questions covering single and multiple choice, each with answers and explanations.

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