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Free MLA-C01 practice test: 30 questions with answers

30 original questions for AWS Certified Machine Learning Engineer - Associate, drawn from every topic area. Answer each one to see whether you got it right and why. No sign-up.

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MLA-C01 exam guide: topics, cost and format

All 30 MLA-C01 questions with answers

The same questions as the test above, grouped by exam topic. Open any question to see the answer and explanation.

ML Model Development (8 questions)

  1. Question 1

    A team wants to start from a pretrained open-source model and fine-tune it on its own data within SageMaker with minimal code. Which capability fits best?

    1. ASageMaker JumpStart
    2. BSageMaker Edge Manager
    3. CAmazon Kinesis Video Streams
    4. DAWS Batch array jobs
    Show answer and explanation
    Correct answer: A

    JumpStart provides pretrained models and solution templates that can be fine-tuned or deployed with little code. Edge Manager is for devices, Kinesis Video handles streams, and Batch runs general compute jobs.

  2. Question 2

    A tabular classification project needs a strong baseline quickly, with automatic feature processing and model selection. Which SageMaker feature should be used?

    1. ASageMaker Serverless Inference
    2. BSageMaker Ground Truth Plus
    3. CSageMaker Autopilot
    4. DSageMaker Neo
    Show answer and explanation
    Correct answer: C

    SageMaker Autopilot automatically explores preprocessing and model candidates for tabular data and produces a ranked set of models with notebooks. Neo compiles models for hardware, Serverless Inference hosts models, and Ground Truth Plus manages labelling.

  3. Question 3

    A training job must search across learning rates and batch sizes to find the best validation accuracy. Which SageMaker feature runs this search?

    1. ASageMaker Edge Manager for device fleets
    2. BSageMaker Clarify bias report for a dataset
    3. CAutomatic model tuning (hyperparameter tuning)
    4. DSageMaker Model Registry for versioning
    Show answer and explanation
    Correct answer: C

    Automatic model tuning runs many training jobs over a hyperparameter range and optimises an objective metric. Clarify analyses bias, Model Registry tracks versions, and Edge Manager manages devices.

  4. Question 4

    A deep learning model is too large to train in a reasonable time on one GPU. Which approach is most appropriate in SageMaker?

    1. AReduce the training dataset to ten rows so each epoch finishes quickly on one GPU instance
    2. BDisable GPUs and train on a single CPU core to keep the model memory footprint small
    3. CTrain the model for one pass over the data and skip validation entirely to save compute
    4. DDistributed training across multiple instances using data or model parallelism
    Show answer and explanation
    Correct answer: D

    Distributed training splits work across multiple GPUs or instances, using data parallelism or model parallelism, to cut wall-clock time. Shrinking the data or removing accelerators does not solve the scaling problem, and skipping validation hides overfitting.

  5. Question 5

    A model overfits: training accuracy is very high, but validation accuracy is much lower. Which change most directly addresses this?

    1. AAdd regularization, use early stopping, or gather more representative training data
    2. BIncrease the learning rate by ten times to speed up convergence on the full training data
    3. CEvaluate the model exclusively on the training data to confirm the fit is strong and reliable
    4. DRemove regularization and train for longer so the model can memorize the training set more thoroughly
    Show answer and explanation
    Correct answer: A

    Regularization, early stopping, and more representative data reduce the gap between training and validation performance. Removing regularization, raising learning rates, and evaluating on training data all worsen or hide overfitting.

  6. Question 6

    A team must track each trained model version, its metrics, and its approval status before deployment. Which SageMaker capability provides this?

    1. AAmazon S3 Object Lock
    2. BAWS Glue crawlers
    3. CSageMaker Model Registry
    4. DAmazon CloudWatch dashboards only
    Show answer and explanation
    Correct answer: C

    Model Registry groups model versions with metadata, metrics, and approval status, which supports governed promotion to production. The other services store data or metrics but do not manage model approval workflows.

  7. Question 7

    A team wants a baseline evaluation of a trained classifier that reports standard metrics such as precision, recall, and AUC on a held-out test set. Which approach fits best?

    1. AReport just the number of training epochs completed during the full run
    2. BUse the validation metric recorded after the first epoch as the final score
    3. CReport the metrics computed from the training run's logs after fitting
    4. DCompute the metrics on a held-out test set that the model never saw during training
    Show answer and explanation
    Correct answer: D

    A held-out test set that was excluded from training gives an unbiased estimate of performance. Training-run metrics and early-epoch values are optimistic or incomplete.

  8. Question 8

    Which technique reduces model size and inference latency for deployment to resource-constrained devices?

    1. AIncreasing the batch size during inference to raise request throughput
    2. BQuantization or pruning, then compilation for the target hardware
    3. CStoring each prediction in a database table so results can be queried later
    4. DAdding more layers to the network to capture deeper features in the input data
    Show answer and explanation
    Correct answer: B

    Quantization reduces numerical precision and pruning removes weights, both shrinking the model, and compilation adapts it to the target hardware. Adding layers increases size, and the other options do not reduce model footprint.

Data Preparation for Machine Learning (8 questions)

  1. Question 9

    A team stores training data as thousands of small CSV files in Amazon S3, and training jobs read the data slowly. Which change most improves read throughput?

    1. AConvert the data to larger partitioned columnar files such as Parquet
    2. BIncrease the number of SageMaker instances without changing the files
    3. CMove the files into S3 Glacier Instant Retrieval
    4. DCompress each small file separately with gzip
    Show answer and explanation
    Correct answer: A

    Many small objects create overhead per read, and partitioned columnar formats like Parquet let jobs read only the needed columns and partitions. Compression alone or more instances do not fix the small-file problem.

  2. Question 10

    A data scientist needs to clean and transform a tabular dataset visually, with a preview of each step, before exporting features for training. Which SageMaker capability fits best?

    1. ASageMaker Clarify
    2. BSageMaker Ground Truth
    3. CSageMaker Model Monitor
    4. DSageMaker Data Wrangler
    Show answer and explanation
    Correct answer: D

    Data Wrangler provides a visual interface to import, transform, and analyse tabular data with previews, and it exports the flow to a processing job or pipeline. Model Monitor watches deployed models, Ground Truth labels data, and Clarify analyses bias and explainability.

  3. Question 11

    Features used in training must be identical when the same features are read for real-time inference. Which SageMaker component is designed to store and serve features consistently for both?

    1. AAmazon Athena views only
    2. BSageMaker Feature Store
    3. CSageMaker Edge Manager
    4. DAWS Glue crawlers only
    Show answer and explanation
    Correct answer: B

    SageMaker Feature Store keeps an online store for low-latency inference and an offline store for training, so both use the same feature definitions. Athena views, Edge Manager, and crawlers do not serve features to inference endpoints.

  4. Question 12

    A labelling project needs human annotators to label images, with managed workforces and quality checks. Which service should be used?

    1. AAmazon Rekognition Custom Labels training only
    2. BSageMaker Ground Truth
    3. CAWS Glue DataBrew only
    4. DAmazon Comprehend
    Show answer and explanation
    Correct answer: B

    Ground Truth manages labelling jobs with workforces, annotation tooling, and consensus or quality controls. Rekognition trains models rather than providing labelling workforces, and Comprehend performs text analysis.

  5. Question 13

    Which two actions reduce the risk of data leakage between training and test data? (Choose two.)

    1. AFit scalers and imputers on the training split only, then apply them to the test split
    2. BFit scalers on the entire dataset before splitting
    3. CInclude the target column as an input feature
    4. DSplit data randomly even for time-ordered records when the data is time series
    5. EUse a time-based split for time-ordered records
    Show answer and explanation
    Correct answer: A, E

    Fitting preprocessing on training data only prevents test statistics from leaking into training, and a time-based split keeps the future out of training for time-ordered data. Fitting on the full dataset, using the target as an input, and random splits of time series each leak information.

  6. Question 14

    Which AWS service provides a serverless data catalog and crawlers that discover schemas for S3 datasets used by Athena and EMR?

    1. AAWS Snowball
    2. BAmazon FSx for Windows File Server
    3. CAWS Glue Data Catalog
    4. DAmazon Redshift Spectrum only
    Show answer and explanation
    Correct answer: C

    The AWS Glue Data Catalog stores table definitions and schemas, and crawlers populate it from S3 data. Athena and EMR use the catalog to query the same datasets. The other services do not provide that metadata layer.

  7. Question 15

    A training dataset is heavily imbalanced, with 98% negative examples. Which approach is most appropriate before training?

    1. AIgnore the imbalance because overall accuracy stays high on this data
    2. BRely on accuracy as the single evaluation metric for comparing models
    3. CDelete most of the negative examples so the classes become equal size before training
    4. DApply resampling or class weighting, and evaluate with precision, recall, or F1
    Show answer and explanation
    Correct answer: D

    Resampling or class weights help the model learn the minority class, and metrics such as precision, recall, and F1 expose poor performance on it. Accuracy can look high while the model misses every positive case, and deleting data discards information.

  8. Question 16

    Personally identifiable information appears in a training dataset stored in S3. Which action reduces the risk before training?

    1. AIncrease the instance size for the training job to add RAM
    2. BDetect and redact or tokenize PII before the data is used for training
    3. CDisable encryption on the bucket to speed up reads during training
    4. DMake the bucket publicly readable so the whole team can audit it
    Show answer and explanation
    Correct answer: B

    Detecting and redacting or tokenizing PII before training keeps sensitive values out of the model and its artifacts. Public access, larger instances, and disabled encryption each increase exposure or do nothing for privacy.

Monitoring, Maintenance, and Security (7 questions)

  1. Question 17

    Which two practices help detect model drift after deployment? (Choose two.)

    1. AIgnore changes in input data
    2. BDisable logging of predictions
    3. CRetrain only once when the model is deployed
    4. DCompare live input distributions against the training baseline
    5. EMonitor prediction quality against ground truth labels when available
    Show answer and explanation
    Correct answer: D, E

    Comparing live inputs with the training baseline reveals data drift, and tracking quality against labelled outcomes reveals performance drift. Ignoring inputs, disabling logs, and retraining only once remove the signals needed to notice drift.

  2. Question 18

    A deployed model's predictions have become less accurate over several weeks, and the team wants alerts when input feature distributions shift. Which SageMaker capability provides this?

    1. ASageMaker Neo Runtime
    2. BSageMaker Ground Truth Plus
    3. CSageMaker JumpStart Hub
    4. DSageMaker Model Monitor
    Show answer and explanation
    Correct answer: D

    Model Monitor captures endpoint data, compares it with a baseline, and raises alerts on data quality and drift. Ground Truth labels data, JumpStart provides models, and Neo compiles models.

  3. Question 19

    A team must ensure that only approved model versions reach production and that every deployment is auditable. Which approach meets this?

    1. ARegister each model version and require an approval status before deployment, with logs in AWS CloudTrail
    2. BOverwrite the production model artifact in place on the live endpoint after each training run, without versioning it
    3. CDeploy whatever model binary happens to be in the data scientist's notebook workspace at the time of the release
    4. DShare the trained model file through an unauthenticated public S3 link that remains valid for seven days, sent to partners
    Show answer and explanation
    Correct answer: A

    Registering versions with an approval gate controls what can be deployed, and CloudTrail records the API activity that makes the change. The other approaches allow unreviewed or untracked deployments.

  4. Question 20

    A SageMaker training job must access data in S3 without traffic crossing the public internet. Which configuration supports this?

    1. ARun the job in a VPC with VPC endpoints for S3 and SageMaker
    2. BMake the bucket public so the job can read it
    3. CRoute the job through a public NAT gateway with an open security group
    4. DDisable networking for the job entirely
    Show answer and explanation
    Correct answer: A

    Running in a VPC with gateway and interface endpoints keeps S3 and API traffic on the AWS network. A public NAT route or a public bucket sends the traffic over the internet, and disabling networking stops the job from reading data.

  5. Question 21

    A team needs to know which user or role invoked a SageMaker API to update an endpoint. Which service records this?

    1. AAmazon Macie
    2. BAWS Budgets API
    3. CAmazon Polly TTS
    4. DAWS CloudTrail
    Show answer and explanation
    Correct answer: D

    CloudTrail logs management API calls with the identity, time, and parameters, which supports auditing endpoint changes. Macie, Budgets, and Polly do not record SageMaker API activity.

  6. Question 22

    A deployed model's latency rose sharply after a traffic increase. Which Amazon CloudWatch metric is the first to check on the endpoint?

    1. AModelLatency and invocation counts for the endpoint variant
    2. BBucket object count and storage size for the S3 training data bucket
    3. CNumber of notebook instances running in the account
    4. DGlue crawler run count and failure count across the ETL catalog
    Show answer and explanation
    Correct answer: A

    ModelLatency and invocation metrics show whether the model itself is slower under the new load, which guides scaling decisions. The other metrics do not describe endpoint behaviour.

  7. Question 23

    A team wants to lower the cost of a steady, long-running training workload that can tolerate interruptions. Which option is most appropriate?

    1. ADedicated Hosts reserved for each training job run
    2. BManaged Spot Training with checkpointing to Amazon S3
    3. CA notebook instance left running for one month
    4. DOn-Demand instances running without checkpoints
    Show answer and explanation
    Correct answer: B

    Managed Spot Training uses spare capacity at a discount, and checkpoints let the job resume after interruptions. On-demand without checkpoints pays full price and loses progress, while dedicated hosts and idle notebooks increase cost.

Deployment and Orchestration of ML Workflows (7 questions)

  1. Question 24

    A team needs to score a nightly file of ten million records and does not need real-time responses. Which option fits best?

    1. AA WebSocket API in front of the model endpoint
    2. BAn interactive notebook kernel running on a persistent instance
    3. CA batch transform job that reads input from Amazon S3
    4. DA real-time endpoint with autoscaling policies
    Show answer and explanation
    Correct answer: C

    Batch transform processes large datasets offline from S3 and writes results back, with no endpoint to keep running. A real-time endpoint or WebSocket API is designed for low-latency requests, and notebooks are for interactive work.

  2. Question 25

    A team needs a real-time endpoint for a model whose traffic is low at night and high during the day. Which option lets the endpoint scale with demand?

    1. ARunning the model on a single notebook instance with no autoscaling
    2. BManual scaling by an on-call engineer who adjusts the instance count by hand each morning
    3. CFixed capacity sized for peak traffic, kept running around the clock
    4. DEndpoint auto scaling with a target metric such as invocations per instance
    Show answer and explanation
    Correct answer: D

    Auto scaling adjusts the number of instances to match invocation load, which balances latency and cost across the day. Fixed peak capacity wastes money at night, and manual or notebook-based serving does not meet production needs.

  3. Question 26

    A workflow must train a model, evaluate it, and deploy it only if the accuracy exceeds a threshold, with each run tracked. Which SageMaker capability orchestrates this?

    1. ASageMaker Pipelines
    2. BSageMaker Clarify
    3. CAWS Glue DataBrew
    4. DSageMaker Edge Manager
    Show answer and explanation
    Correct answer: A

    SageMaker Pipelines defines ML workflows as connected steps, including conditional steps that gate deployment on metrics, and it records each execution. Clarify analyses bias, Edge Manager manages devices, and DataBrew prepares data.

  4. Question 27

    A team wants to host a model at the edge on factory devices with limited connectivity. Which SageMaker capability helps manage and monitor models on those devices?

    1. ASageMaker Edge Manager
    2. BSageMaker Feature Store
    3. CAmazon Athena
    4. DSageMaker Serverless Inference
    Show answer and explanation
    Correct answer: A

    Edge Manager packages models for edge devices and manages their deployment and monitoring. Serverless Inference runs in the cloud, Feature Store serves features, and Athena queries data.

  5. Question 28

    A model must answer requests that are sporadic, with long idle periods and occasional bursts, and the team wants no capacity to manage. Which hosting option fits best?

    1. AA bare-metal server in a colocation facility
    2. BAn EC2 instance started by hand each time
    3. CSageMaker Serverless Inference
    4. DA real-time endpoint on a dedicated instance that runs all the time
    Show answer and explanation
    Correct answer: C

    Serverless Inference provisions capacity on demand and scales to zero between bursts, so idle periods cost nothing. A dedicated always-on endpoint pays for idle time, and manual or colocated servers add operational work.

  6. Question 29

    A new model version must be promoted to production with a small share of traffic first, and rolled back quickly if errors rise. Which deployment strategy fits?

    1. ADeploy the new version first to a notebook instance for interactive checks
    2. BCanary deployment that routes a small percentage of traffic to the new variant
    3. CShift the entire production traffic to the new version in one cutover without a weighted split
    4. DDelete the existing production endpoint before provisioning the replacement endpoint in place
    Show answer and explanation
    Correct answer: B

    A canary sends a small share of traffic to the new version, so problems affect few users and rollback is quick. Cutting over all at once, deleting the old endpoint first, or testing only in a notebook each removes that safety margin.

  7. Question 30

    A company needs to generate predictions for a large dataset stored in Amazon S3 without maintaining a persistent endpoint. Which approach fits best?

    1. AA persistent real-time endpoint that is left idle
    2. BA WebSocket API connected to the model
    3. CA batch transform job
    4. DManual predictions in a spreadsheet
    Show answer and explanation
    Correct answer: C

    Batch transform reads inputs from S3, runs inference on the whole dataset, and writes outputs back, without keeping an endpoint running. The other options add cost or rely on manual steps.

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