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Free DSA-C03 practice test: 30 questions with answers
30 original questions for SnowPro Advanced: Data Scientist, drawn from every topic area. Answer each one to see whether you got it right and why. No sign-up.
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All 30 DSA-C03 questions with answers
The same questions as the test above, grouped by exam topic. Open any question to see the answer and explanation.
Machine Learning Methods (4 questions)
Question 1
A business wants to predict whether a customer will churn next month, using labeled historical records. Which machine learning task fits?
- ABinary classification
- BTime series forecasting of revenue only
- CClustering with no labels
- DAnomaly detection with no target
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Correct answer: APredicting a yes or no outcome from labeled history is binary classification. Clustering ignores labels, revenue forecasting predicts a value over time, and anomaly detection does not use the churn label.
Question 2
A team wants to group customers into segments without any labels. Which approach fits?
- ASupervised classification
- BReinforcement learning with rewards
- CLogistic regression
- DClustering such as k-means
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Correct answer: DClustering finds groups in unlabeled data. Logistic regression and classification need labels, and reinforcement learning uses rewards.
Question 3
A regression model for house prices performs well on training data but poorly on test data. Which technique helps most?
- ATraining on a reduced set of records
- BRemoving the held-out test set entirely
- CAdding more random noise to the training labels
- DRegularization such as L2 or L1 penalties
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Correct answer: DRegularization reduces overfitting by discouraging overly complex models. Adding label noise, fewer data points and removing the test set do not address generalization.
Question 4
A gradient boosting model is trained, and the team wants to choose the number of trees. Which technique helps select this without touching the test set?
- AChoosing the number that gives the best test score
- BUsing the training loss alone
- CEarly stopping using a validation set
- DPicking the largest number possible
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Correct answer: CEarly stopping on a validation set chooses the number of trees without using the test set. Tuning on the test set leaks information, training loss alone keeps decreasing, and maximum trees may overfit.
Snowflake Platform for Data Science (4 questions)
Question 5
Which two statements about Snowflake micro-partitions are accurate? (Choose two.)
- AMicro-partitions are only available in external tables
- BMicro-partitions prevent any query pruning
- CMicro-partitions are stored with metadata that enables pruning
- DData is automatically organized into micro-partitions as it is loaded
- EMicro-partitions must be managed manually by the user for all tables
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Correct answer: C, DMetadata on micro-partitions enables pruning, and loading organizes data automatically. Users do not manage them manually, they apply to native tables, and they enable rather than prevent pruning.
Question 6
Which two factors affect the performance of a query on a large table? (Choose two.)
- AThe warehouse size and available memory
- BThe color of the result grid
- CThe number of users who logged in today
- DThe font size in the query editor
- EThe filters used and how well they match the clustering or partitioning
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Correct answer: A, EFilter selectivity relative to clustering and warehouse resources drive query performance. Result colors, login counts and editor fonts do not.
Question 7
A query in Snowflake runs slowly on a large table with frequent filters on a date column. Which feature helps prune micro-partitions most effectively?
- AAdding more users to the same role
- BRenaming the table to a new name
- CClustering the table on the date column
- DTurning off Time Travel retention
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Correct answer: CClustering keys organize micro-partitions so filters on the key scan fewer partitions. User counts, names and Time Travel settings do not improve pruning.
Question 8
Which Snowflake component provides the compute resources that execute queries and Snowpark code?
- AVirtual warehouse
- BShared database
- CInternal stage
- DTable change stream
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Correct answer: AVirtual warehouses provide compute for queries and Snowpark code. Stages store files, shares expose data, and streams capture changes.
Model Lifecycle and Operations (4 questions)
Question 9
Which two steps are typically part of a feature engineering pipeline? (Choose two.)
- ACreating and validating derived features
- BPrinting the feature names on paper
- CChanging the table's comment color
- DDeleting the source data after each run
- ECleaning and transforming raw data
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Correct answer: A, ECleaning, transforming and validating derived features form the core of feature engineering. Printing names, color changes and deleting source data are not pipeline steps.
Question 10
A model in production shows declining performance over several weeks. Which first step is most appropriate?
- AComparing recent input distributions and labels with the training baseline to diagnose drift
- BReplacing the production model with a newer architecture without analysis of the cause
- CRetraining immediately on the same old data without checking the cause of the decline
- DTurning off the drift and performance monitoring dashboards for the live endpoint
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Correct answer: ADiagnosing drift by comparing recent inputs and labels with the baseline guides the right fix. Retraining on old data, disabling monitoring and replacing without analysis do not address the cause.
Question 11
A retraining pipeline must run only when the model's performance drops below a threshold on fresh labeled data. Which design fits?
- AScheduling a retraining task to run every second regardless of observed model metrics
- BA conditional task that evaluates performance and triggers retraining when the threshold is crossed
- CRetraining whenever a manager informally remembers to request it during a quarterly review meeting and approves it
- DFreezing the deployed model weights permanently after the initial release, leaving it unchanged across the service life
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Correct answer: BA conditional pipeline triggers retraining based on measured performance, which is efficient and responsive. Constant retraining, memory-based triggers and never retraining do not follow the requirement.
Question 12
A model must be deployed so that predictions are logged with the model version and input features, enabling later audits. Which practice meets this?
- ALogging predictions as printed screenshots of the monitoring dashboard into a shared folder
- BStoring predictions temporarily in process memory on each serving container without persistence
- CNot logging predictions to save storage costs on the serving infrastructure during peak traffic
- DLogging predictions with version identifiers and input snapshots to a governed table
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Correct answer: DLogging with version and inputs to a governed table supports audits and debugging. Screenshots, memory-only storage and no logs do not support audit needs.
Data Governance and Sharing (3 questions)
Question 13
A data scientist in another account needs read access to a curated feature table without copying the data. Which Snowflake feature fits?
- ACreating a public web page with the data
- BGiving the other account the owner role
- CExporting the table to CSV files in email
- DSecure data sharing
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Correct answer: DSecure data sharing exposes data to another account without copying it, and access can be limited. Email exports, public pages and owner roles create copies or excessive access.
Question 14
A curated dataset must be restricted so that users see only rows for their own region. Which feature implements this at the table level?
- AA separate table for every region with no controls
- BRow access policies based on the user's role or region mapping
- CColumn masking policies applied to every sensitive column
- DA stored procedure that users must remember to call before querying the table
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Correct answer: BRow access policies filter rows based on identity or role, which enforces the requirement. Column masking hides values rather than rows, while manual calls and separate tables do not enforce access.
Question 15
A column contains sensitive data, and the data science team needs aggregated results only. Which mechanism prevents row-level exposure?
- AGranting the full table to every analyst role in the account
- BStoring the sensitive column as an image file in a binary blob
- CCopying the column values to a public external stage for analysts
- DAggregation policies or secure views that expose only aggregated outputs
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Correct answer: DAggregation policies or secure views limit exposure to aggregated results. Full access, public stages and image storage expose or obscure data inappropriately.
Snowflake Data Science Functions (3 questions)
Question 16
A data scientist needs to compute a rolling seven-day average of sales per store in SQL. Which construct is appropriate?
- AA GROUP BY across the full date column with no ordering or frame
- BA window function with partitioning by store and an ordered range of seven days
- CA cross join pairing each store with each calendar date before aggregating
- DA DISTINCT on the sales amount column to remove duplicate sale values
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Correct answer: BWindow functions with partitions and ordered ranges compute rolling averages per group. GROUP BY collapses rows, cross joins explode data, and DISTINCT does not compute averages.
Question 17
A feature needs to be calculated for each row from the values of the previous row in the same customer's history. Which SQL function enables this?
- ALAG
- BMAX without partition
- CSUM over all rows only
- DCOUNT DISTINCT on the whole table
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Correct answer: ALAG returns the prior row's value within an ordered partition. The other functions do not return the previous row's value.
Question 18
A categorical feature is derived from a JSON column with nested keys. Which Snowflake approach extracts the value?
- AConverting the JSON column to an image for visualization
- BIgnoring nested keys and treating the whole column as a single string
- CPath notation or the FLATTEN function to access nested fields
- DOpening the JSON in a text editor manually for each row
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Correct answer: CPath notation and FLATTEN access nested fields in semi-structured data. Editors, images and ignoring keys do not produce features in SQL.
Data Preparation and Feature Engineering (3 questions)
Question 19
A dataset has a column with many missing values in a numeric feature. Which Snowpark or SQL approach imputes the values with the training median without leaking test information?
- AComputing the median on the full dataset before splitting
- BComputing the median on the training split and applying it to both splits
- CReplacing missing values with the text string 'missing' in a numeric column
- DDeleting all rows with any missing value across the table
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Correct answer: BComputing the imputation statistic on the training split avoids leakage from the test split. Full-dataset statistics leak information, text placeholders break numeric types, and deleting all incomplete rows can discard most of the data.
Question 20
A categorical column has thousands of distinct values. Which approach keeps the model input manageable?
- AUsing the raw customer name strings as ordinal numeric codes
- BDropping the column outright without statistical analysis
- CGrouping rare categories into an other bucket and encoding the rest
- DOne-hot encoding every distinct value with no cap on columns
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Correct answer: CGrouping rare categories and encoding the frequent ones controls dimensionality. Unlimited one-hot encoding creates huge inputs, raw names are not meaningful numbers, and dropping without analysis discards signal.
Question 21
A time-based feature must be computed for each customer using only events that occurred before the prediction date. Which technique avoids leakage?
- AUsing window functions with a range restricted to earlier timestamps
- BComputing features from the final calendar month of transaction data for scoring
- CAveraging across each event, including future ones recorded after scoring
- DUsing the label column as an input to compute the feature via window join
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Correct answer: AWindowed calculations limited to prior events prevent future information from entering features. Using future events, labels and only the final month introduce leakage or bias.
Model Development in Snowflake (3 questions)
Question 22
A team wants to train a scikit-learn style model inside Snowflake using the Snowpark ML library. Which benefit is most accurate?
- ATraining runs on the user's local laptop with a Python notebook
- BTraining can run on Snowflake compute close to the data, reducing data movement
- CTraining requires exporting the full data set to an external ML host first
- DTraining is restricted to deep learning frameworks such as PyTorch
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Correct answer: BSnowpark ML trains models on Snowflake compute close to the data, which reduces movement. The other options describe unnecessary exports or incorrect limitations.
Question 23
A trained model must be versioned and recorded with its metrics and lineage so that the team can compare versions. Which Snowflake capability supports this?
- AThe model registry in Snowflake ML
- BA comment on the warehouse
- CA shared folder with the model's file name
- DA screenshot of the metrics
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Correct answer: AThe model registry records versions, metadata and metrics for comparison and deployment. File names, warehouse comments and screenshots do not provide structured model lineage.
Question 24
A model needs to be used for batch scoring of a large table inside Snowflake. Which approach is most efficient?
- AConverting the feature table into image tensors before batch scoring begins
- BScoring just the first row of each partition and skipping the remaining rows
- CRunning inference from the registry against the table in parallel on warehouse compute
- DPulling every row to a local machine and scoring one row at a time in pandas
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Correct answer: CRegistry-based batch inference on warehouse compute scales with the table and avoids data movement. Local row-by-row scoring, image conversion and scoring one row do not meet the requirement.
Data Science Workflow in Snowflake (3 questions)
Question 25
A data scientist wants to run Python feature engineering next to the data stored in Snowflake without exporting it to a separate server. Which Snowflake capability fits best?
- ASnowpark for Python, which runs DataFrame code pushed down to Snowflake compute
- BRunning the code inside the browser's local storage with a client-side session cache
- CExporting nightly full copies of each table to a local laptop CSV file for offline analysis
- DCreating a separate external database replica for every modeling experiment and syncing it nightly
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Correct answer: ASnowpark pushes DataFrame operations to Snowflake compute so data does not need to leave the platform. Exporting to laptops, external copies and browser storage move or duplicate sensitive data unnecessarily.
Question 26
Which Snowpark object represents a lazily evaluated, distributed table-like collection of rows that is transformed before execution?
- AStage
- BDataFrame
- CWarehouse
- DTask
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Correct answer: BA Snowpark DataFrame is lazily evaluated and executes transformations in Snowflake when an action such as collect runs. A stage stores files, a warehouse provides compute, and a task schedules work.
Question 27
A DataFrame transformation chain is defined in Snowpark but nothing runs in the warehouse until a specific action is called. What is this behavior called?
- ALazy evaluation
- BCloning on write
- CEager replication
- DTime travel
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Correct answer: ASnowpark defers execution until an action such as collect or show requests results, which lets Snowflake optimize the query. Replication, cloning and time travel are different features.
Data Quality and Monitoring (3 questions)
Question 28
A data scientist wants to detect when a numeric feature has many null values after a pipeline change. Which practice helps most?
- ALooking at the feature table manually after a downstream model fails in production
- BAssuming that null values in the feature column reflect correct upstream business logic by default
- CAdding data quality checks such as null-rate thresholds that alert when exceeded
- DDeleting the feature column from the training and serving datasets
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Correct answer: CNull-rate checks with alerts catch quality issues early. Reactive checks, assumptions and deletion do not provide reliable early detection.
Question 29
Which metric best indicates that a classification model's predicted class distribution has shifted over time?
- AThe number of feature columns in the training table after schema changes and their data types
- BThe model's serialized artifact file size on disk in the stage registry over time
- CThe number of downstream BI dashboards that reference the model in Snowsight
- DMonitoring the proportion of predicted classes compared with the baseline distribution
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Correct answer: DComparing predicted class proportions with the baseline reveals distribution shifts. Column counts, file sizes and dashboard counts do not measure predicted classes.
Question 30
A table's row count dropped unexpectedly after a load. Which Snowflake capability helps investigate what changed?
- AQuerying the table's historical state with Time Travel and reviewing the query history
- BChanging the table's comment and description text to document the new nightly load
- CDeleting the table and recreating it immediately from the raw source files
- DIgnoring the drop in row count because normal counts vary between daily loads
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Correct answer: ATime Travel and query history reveal what changed and when. Deleting or ignoring the drop loses evidence, and comments do not show changes.