AWS Certified Machine Learning Specialty — Free Practice Questions

152 free AWS Certified Machine Learning Specialty practice questions with detailed answer explanations. Covers all exam domains, no signup needed.

152 questions · answers explained · free to practise · AWS AI & ML certification hub

⚠️ This exam has retired

AWS Certified Machine Learning – Specialty (MLS-C01) retired on 31 March 2026. These questions remain useful AWS machine-learning study material, but they no longer map to a bookable exam. Candidates certifying today should look at AWS Certified Machine Learning Engineer – Associate or AWS Certified Generative AI Developer – Professional.

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Sample questions with answers

8 of the 152 questions in this set, with the correct answer marked and explained.

1. A company is setting up a system to manage all of the datasets it stores in Amazon S3. The company would like to automate running transformation jobs on the data and maintaining a catalog of the metadata concerning the datasets. The solution should require the least amount of setup and maintenance. Which solution will allow the company to achieve its goals?

  • Create an AWS Glue crawler to populate the AWS Glue Data Catalog. Then, author an AWS Glue ETL job, and set up a schedule for data transformation jobs.
    AWS Glue is the correct answer because this option requires the least amount of setup and maintenance since it is serverless, and it does not require management of the infrastructure. Refer to this link for supporting information. A, C, and D are all solutions that can solve the problem, but require more steps for configuration, and require higher operational overhead to run and maintain.
  • Create an Amazon EMR cluster with Apache Hive installed. Then, create a Hive metastore and a script to run transformation jobs on a schedule.
    This works, but it means provisioning and paying for an EMR cluster to do what Glue does serverless. The question asks for the least operational overhead.
  • Create an AWS Data Pipeline that transforms the data. Then, create an Apache Hive metastore and a script to run transformation jobs on a schedule.
    Data Pipeline is a legacy orchestration service, and pairing it with a self-managed Hive metastore adds two components Glue replaces with one.
  • Create an Amazon EMR cluster with Apache Spark installed. Then, create an Apache Hive metastore and a script to run transformation jobs on a schedule.
    Same objection as the other EMR option: a cluster you have to size, patch and pay for, where a managed crawler and ETL job would do.

2. Which service in the Kinesis family allows you to easily load streaming data into data stores and analytics tools?

  • Kinesis Data Analytics
    Data Analytics runs SQL or Flink queries over a stream. It analyses data in flight rather than delivering it to a destination.
  • Kinesis Firehose
    Kinesis Firehose is perfect for streaming data into AWS and sending it directly to its final destination - places like S3, Redshift, Elastisearch, and Splunk Instances.
  • Kinesis Streams
    Data Streams is the durable buffer that holds records for consumers to read. Getting them into S3, Redshift or OpenSearch still needs something else — that something is Firehose.
  • Kinesis Video Streams
    Purpose-built for video and other time-encoded media, not general-purpose delivery to data stores.

3. Your organization has a standalone Javascript (Node.js) application that streams data into AWS using Kinesis Data Streams. You notice that they are using the Kinesis API (AWS SDK) over the Kinesis Producer Library (KPL). What might be the reasoning behind this?

  • The Kinesis API (AWS SDK) provides greater functionality over the Kinesis Producer Library.
    The reverse is true. The KPL adds aggregation, batching, retries and CloudWatch metrics on top of the raw API.
  • The Kinesis API (AWS SDK) runs faster in Javascript applications over the Kinesis Producer Library.
    Throughput is not the deciding factor here. The KPL's aggregation typically gives higher throughput where it can be used at all.
  • The Kinesis Producer Library cannot be integrated with a Javascript application because of its asynchronous architecture.
    Asynchrony is not the obstacle — Node.js is comfortable with async. The obstacle is that the KPL is a Java process.
  • The Kinesis Producer Library must be installed as a Java application to use with Kinesis Data Streams.
    The KPL must be installed as a Java application before it can be used with your Kinesis Data Streams. There are ways to process KPL serialized data within AWS Lambda, in Java, Node.js, and Python, but not if these answers mentions Lambda.

4. You have been tasked with capturing two different types of streaming events. The first event type includes mission-critical data that needs to immediately be processed before operations can continue. The second event type includes data of less importance, but operations can continue without immediately processing. What is the most appropriate solution to record these different types of events?

  • Capture both events with the PutRecords API call.
    PutRecords is the right choice for the latency-sensitive stream, but using it for everything forgoes the KPL's aggregation, which is what makes high-volume ingestion efficient.
  • Capture the mission critical events with the Kinesis Producer Library (KPL) and the second event type with the Putrecords API call.
    Backwards. The KPL buffers records before sending in order to aggregate them, which adds latency — exactly what mission-critical events cannot afford.
  • Capture both event types using the Kinesis Producer Library (KPL).
    The KPL's RecordMaxBufferedTime introduces deliberate delay. Acceptable for bulk data, not for events that must arrive immediately.
  • Capture the mission critical events with the PutRecords API call and the second event type with the Kinesis Producer Library (KPL).
    The question is about sending data to Kinesis synchronously vs. asynchronously. PutRecords is a synchronous send function, so it must be used for the first event type (critical events). The Kinesis Producer Library (KPL) implements an asynchronous send function, so it can be used for the second event type. In this scenario, the reason to use the KPL over the PutRecords API call is because: KPL can incur an additional processing delay of up to RecordMaxBufferedTime within the library (user-configurable). Larger values of RecordMaxBufferedTime results in higher packing efficiencies and better performance. Applications that cannot tolerate this additional delay may need to use the AWS SDK directly. For more information about using the AWS SDK with Kinesis Data Streams, see Developing Producers Using the Amazon Kinesis Data Streams API with the AWS SDK for Java. For more information about RecordMaxBufferedTime and other user-configurable properties of the KPL, see Configuring the Kinesis Producer Library.

5. Which visualizations help show composition?

  • Bar chart
  • Stacked area chart
    Visualizing the composition of our data is a great way to show what our data is made of.
  • Stacked bar chart
  • Pie chart

6. Which visualization types are recommended for displaying the distribution of data?

  • Scatter plot
    A histogram is a good visualization type for displaying the single distribution of data. A scatter plot is a good visualization type for displaying multi-distribution data, as it easily shows data clusters, minimum and maximum values, and outliers. A box plot is a good visualization type for displaying multi-distribution data, as it easily shows the minimum, maximum, and mean values of data, as well as outliers.
  • Stacked area chart
  • Box plot
  • Histogram

7. What needs to be done to the following phrase before using it in your machine learning process? The quk BROWN FOX jumped over the lazy dog.

  • Replace each word with a respective n-gram vector
  • Create tokens from each value
    Before we use corpus data in some Machine Learning processes like language translation, sentiment analysis, or spam filtering it is important we properly apply text processing to the data. Some of the important text processing that needs to be done is tokenization. This includes removing stop words — frequent words such as ”the”, ”is”, etc. that do not have specific meaning. Before we use corpus data in some Machine Learning processes like language translation, sentiment analysis, or spam filtering it is important we properly apply text processing to the data. Some of the important text processing that needs to be done is tokenization. This includes converting sentences to words, removing unnecessary punctuation, and removing stop words — frequent words such as ”the”, ”is”, etc. that do not have specific meaning.
  • Apply mapping of stop words
  • Lowercase transformation

8. You are preparing plain text corpus data to use in a NLP process. Which of the following is/are one of the important step(s) to pre-process the text in NLP based projects?

  • Stemming
    Stemming is a rudimentary rule-based process of stripping the suffixes (“ing”, “ly”, “es”, “s” etc) from a word. Stop words are those words which will have no relevance to the context of the data for example is/am/are. Object Standardization is also one of the good ways to pre-process the text by removing things like acronyms, hashtags with attached words, and colloquial slang that typically are not recognized by search engines and models.
  • Word standardization
  • Add random text noise
  • Stop word removal

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