PL-300 Prepare the data Practice Question

Answer analysis

Option-by-option breakdown

For each option: why learners choose it and why it is or isn't the right answer here.

• ✓

  Generate DAX expressions for calculated columns and measures.

  Why this is correct

  Copilot for Power BI interprets natural language descriptions and generates syntactically valid DAX expressions for calculated columns and measures, leveraging the semantic model's schema and relationships. This capability supports data preparation by extending the model with custom logic, such as time intelligence, conditional flags, or ratio metrics, without requiring manual DAX authoring. It also assists with debugging or explaining existing DAX, making it a core feature for data modeling.

• ✓

  Create Power Query M code snippets for common transformations.

  Why this is correct

  Copilot can compose Power Query M code snippets for common transformations, such as merging queries, removing rows/columns, or adding conditional columns, directly in the Power Query editor. By describing the intended transformation in natural language, Copilot produces reusable code that can be inserted into the applied steps, accelerating data shaping tasks. It also provides explanations for existing M steps, helping users understand and refine query logic for data preparation.

• ✗

  Set up incremental refresh policies.

  Why it's wrong here

  Incremental refresh policies in Power BI require manual configuration through the Power BI Desktop 'Incremental refresh' dialog, including defining rangeStart/rangeEnd parameters, partition settings, and data source support. These policies depend on the specific data source and warehouse architecture, and they are managed by the dataset owner; Copilot does not have the ability to apply or modify these system-level settings. Even in the service, setting up incremental refresh is a dataset-level administrative action, not a data preparation step that Copilot can automate.

• ✓

  Suggest transformations to clean and shape data.

  Why this is correct

  Copilot analyzes the actual data values and column profiles to suggest transformations like removing empty columns, splitting text, changing data types, or filtering outliers. These recommendations appear in the Power Query editor or through a dedicated pane, and users can accept or refine them before applying. This streaming and interactive guidance accelerates data cleanup and normalization, which is fundamental to data preparation.

• ✗

  Configure data source credentials for refresh.

  Why it's wrong here

  Data source credentials are stored as security settings in the Power BI service (or gateway) and must be entered manually by the dataset owner or administrator, using the appropriate authentication method (e.g., OAuth, key, database login). Copilot operates only in the editing context and does not have access to, nor the permission to alter, these credential stores or gateway settings. Additionally, credential configuration is a refresh-time operation outside the scope of data preparation and is strictly a data management task.

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