PL-300 Visualize and analyze the data Practice Test 15 — 15 Questions

Question 1

You are designing a Power BI report that will be viewed on mobile devices. The report contains a complex scatter plot with many data points. Users complain that the visual is hard to interact with on small screens. What is the best approach to improve the mobile experience?

Choose an answer to begin — your selection is scored in the full session.

Accepted Answer

Create a separate mobile layout and replace the scatter plot with a simpler visual like a line chart.. The correct option is D: create a separate mobile layout and replace the scatter plot with a simpler visual like a line chart. Power BI's mobile layout feature lets you design a phone-optimized view of the report, and swapping a dense scatter plot for a simpler visual such as a line chart reduces clutter and improves touch interaction on small screens. Options A, B, and C do not solve the core problem: bookmarks still show the complex scatter plot, a slicer does not reduce visual complexity, and enlarging the scatter plot to fill the screen makes the many data points even harder to interact with on a small display.

Answer

Use bookmarks to switch between the scatter plot and a table.

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Keep the scatter plot but add a slicer to filter data.

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Increase the size of the scatter plot to fill the screen.

Question 2

You want to create a Power BI report that allows users to ask questions in natural language and get visual answers. Which feature should you enable?

Accepted Answer

Q&A visual. The Q&A visual is the correct choice because it lets report consumers type natural-language questions into a report and receive automatic visual answers, which is exactly the requested capability. It works by interpreting the question against the semantic model and rendering an appropriate chart without requiring users to build visuals manually. The Key influencers visual instead explains which factors drive a metric, and the Decomposition tree is for interactive root-cause breakdowns across dimensions, so neither accepts free-form natural-language questions. Copilot for Power BI can assist with authoring and summaries, but the dedicated in-report feature for natural-language questions and visual answers is the Q&A visual.

Answer

Key influencers visual

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Copilot for Power BI

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Decomposition tree

Question 3

Which TWO of the following are valid ways to create a calculated table in Power BI? (Select two.)

Accepted Answer

Using the CALENDAR function to generate a date table.. Option A is correct because the CALENDAR function is a DAX table-returning function that generates a contiguous date table, and calculated tables are created with DAX table expressions. Option B is correct because DAX table functions such as SUMMARIZE and ADDCOLUMNS return tables and are commonly used in the DAX formula bar to build calculated tables. Option C is incorrect because the 'New Table' button under the Modeling tab expects a DAX table expression, not a Power Query expression. Option D is incorrect because M language in Power Query Editor creates queries/imported tables, not calculated tables. Option E is incorrect because there is no such right-click 'New calculated table' command in the Fields pane.

Answer

Using the 'New Table' button under the 'Modeling' tab and writing a Power Query expression.

Answer

Using M language in Power Query Editor.

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By right-clicking a table in the Fields pane and selecting 'New calculated table'.

Question 4

Which THREE of the following are best practices for designing Power BI reports for accessibility? (Select three.)

Accepted Answer

Ensure tab order is logical for keyboard navigation.. Option B is correct because a logical tab order lets keyboard and screen-reader users move through report elements in a meaningful sequence, which is a core accessibility requirement in Power BI. Option C is correct because high color contrast between text and background ensures content remains legible for users with low vision or color-vision deficiencies, aligning with WCAG contrast guidance. Option E is correct because alt text gives screen readers a textual description of visuals, charts, and images so non-visual users can understand the data being presented. Option A is not appropriate because 3D effects reduce clarity and can distort data perception rather than improve accessibility. Option D is not appropriate because using as many colors as possible harms differentiation for color-blind users and creates visual clutter; accessible designs use a limited, distinguishable palette.

Answer

Use 3D effects to make visuals more engaging.

Answer

Use as many colors as possible to differentiate data.

Question 5

You have a Power BI report that uses a DirectQuery connection to a large SQL Server data warehouse. Users report that slicers and filters are slow to respond. What should you recommend to improve performance?

Accepted Answer

Optimize the SQL queries and add appropriate indexes in the data warehouse.. With DirectQuery, every slicer and filter interaction is translated into a SQL query sent to the source, so performance depends heavily on the underlying SQL Server query efficiency and index availability; optimizing the SQL and adding appropriate indexes reduces query execution time and speeds up slicer/filter responsiveness. Option B does not fit because a live connection is used with Analysis Services (tabular/multidimensional) models, not a SQL Server data warehouse, and it would not improve the underlying query performance. Option C does not fit because increasing Power BI service capacity memory does not address slow source-side SQL execution in DirectQuery. Option D does not fit because switching to Import mode changes the architecture and introduces refresh latency and dataset size limits, rather than directly fixing the DirectQuery query performance issue described.

Answer

Change the connection to a live connection to the data warehouse.

Answer

Increase the memory allocated to the Power BI service capacity.

Answer

Switch the report to Import mode and schedule refreshes.

Question 6

You are building a Power BI report that uses a composite model with a DirectQuery source and an imported local table. You want to create a measure that aggregates data from both sources. What must you ensure?

Accepted Answer

The relationships between tables must be defined correctly.. The correct answer is A: relationships between tables must be defined correctly. In a Power BI composite model, a measure can aggregate data from both a DirectQuery source and an imported local table only when the tables are related through properly defined relationships, which allows the DAX engine to propagate filters across storage-mode boundaries. Without a valid relationship (correct cardinality and cross-filter direction), the measure cannot combine the two sources. Option B is false because composite models explicitly support measures spanning Import and DirectQuery tables. Option C is wrong because composite models are designed to mix storage modes, not force them to match. Option D is unnecessary and would defeat the purpose of using an imported local table.

Answer

You cannot create measures that use columns from both sources.

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Both tables must be set to the same storage mode (DirectQuery or Import).

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The local table must be converted to DirectQuery.

Question 7

You have a Power BI report that uses a calculated column to categorize sales as 'High', 'Medium', or 'Low'. You notice the column is not being refreshed when the underlying data changes. What is the most likely reason?

Accepted Answer

Calculated columns are only refreshed when the dataset is refreshed.. Calculated columns are only refreshed when the dataset is refreshed. In Power BI, a calculated column is computed during dataset processing and its values are stored in the model, so it will not reflect underlying data changes until the dataset is refreshed (or the column is recalculated during that refresh). Option A does not fit because a measure is not stored row-by-row and would not appear as a column that simply fails to refresh. Option C does not fit because incorrect DAX syntax would typically produce an error or blank values, not a stale column. Option D does not fit because calculated columns do not dynamically update regardless of the functions used; the refresh behavior is inherent to how calculated columns are processed.

Answer

The column is defined as a measure instead of a calculated column.

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The DAX syntax for the calculated column is incorrect.

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The calculated column uses a function that does not support dynamic updates.

Question 8

You are designing a Power BI report that will be viewed on mobile devices. The report includes many visuals. What is the best practice for optimizing the report layout for mobile?

Accepted Answer

Create a mobile-optimized layout using the Phone layout view.. Create a mobile-optimized layout using the Phone layout view. Power BI Desktop provides a dedicated Phone layout view where you can rearrange, resize, and hide visuals specifically for portrait mobile screens, ensuring the report is readable and usable on phones without affecting the desktop layout. Options B, C, and D do not address mobile layout optimization: a single table visual is not a layout best practice, bookmarks are for navigation rather than responsive design, and limiting to one visual per page is an arbitrary restriction that does not optimize the mobile experience.

Answer

Use a table visual to display all data.

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Use bookmarks to navigate between different views.

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Reduce the number of visuals to one per page.

Question 9

You have a Power BI dataset with a fact table and multiple dimension tables. You need to ensure that when a user filters by a dimension, the filter propagates correctly to the fact table. What type of relationship should you use?

Accepted Answer

One-to-many from dimension to fact.. The correct option is B: One-to-many from dimension to fact. In a star schema, the dimension table holds unique key values (the "one" side) and the fact table has many rows per key (the "many" side), so a one-to-many relationship from dimension to fact lets filter context propagate from the dimension down to the fact table correctly. Option A describes the same relationship from the opposite direction, which is not how Power BI models it, and it would also be a many-to-one from fact to dimension rather than the required propagation direction. Option C (one-to-one) is wrong because a fact table typically has multiple rows per dimension key, and option D (many-to-many) is unnecessary and would introduce ambiguous filter propagation unless a bridge table is involved.

Answer

Many-to-one from fact to dimension.

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One-to-one between dimension and fact.

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Many-to-many between dimension and fact.

Question 10

You are creating a Power BI report and want to allow users to ask questions about the data using natural language. Which feature should you enable?

Accepted Answer

Q&A visual.. The Q&A visual (option C) is the correct choice because it lets report consumers type natural-language questions and automatically returns answers as visuals, which is exactly the requirement for asking questions about the data in natural language. Quick Insights (A) instead runs automated analytics to surface patterns and anomalies without accepting user questions. The Key Influencers visual (B) is a predefined AI visual that explains which factors drive a metric, not a natural-language query interface. Copilot for Power BI (D) can generate report content and summaries, but the dedicated in-report natural-language question feature is the Q&A visual.

Answer

Quick Insights.

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Key Influencers visual.

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Copilot for Power BI.

Question 11

Which TWO of the following are best practices for designing Power BI reports for accessibility? (Select TWO.)

Accepted Answer

Provide alternative text for visuals.. Option A is correct because providing alternative text (alt text) for visuals lets screen readers announce a meaningful description of each chart, image, or shape, which is a core accessibility requirement in Power BI. Option C is correct because sufficient color contrast between text and background ensures that low-vision users and people viewing reports in bright environments can read content, and Power BI's Accessibility Checker flags insufficient contrast. Option B is not recommended because animations can distract users and may cause issues for people with cognitive or vestibular sensitivities, and they are not an accessibility best practice. Option D is not ideal because relying on color alone to differentiate data points excludes color-blind users; accessible designs should add labels, shapes, or patterns instead. Option E is wrong because small font sizes reduce readability; accessible reports should use legible font sizes rather than shrinking text to fit more data.

Answer

Use animations to draw attention.

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Use a variety of colors to differentiate data points.

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Use small font sizes to fit more data.

Question 12

You have a Power BI report that includes a pie chart. Users complain that it is difficult to compare the sizes of slices. Which visual should you recommend instead to improve comparison?

Accepted Answer

A bar chart.. A bar chart, because bar charts encode values by length along a common baseline, which makes even small differences between categories easy to compare accurately, unlike the angle-based judgments required by pie slices. In Power BI, switching the pie chart to a bar chart (or clustered bar chart) directly addresses the users' difficulty in comparing sizes. A treemap (A) uses area to represent values, which is also harder to compare precisely than length. A donut chart (B) has the same angle-comparison limitation as a pie chart, just with a hole in the middle. A scatter plot (D) shows relationships between two numeric measures rather than comparing parts of a whole, so it does not fit this scenario.

Answer

A treemap.

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A donut chart.

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A scatter plot.

Question 13

You create a Power BI report that includes a page with a matrix visual showing sales by region and product category. You want users to be able to drill down from region to salesperson level. What is the best way to enable this?

Accepted Answer

Add the Salesperson field to the matrix rows hierarchy below Region.. The correct option is C: adding the Salesperson field to the matrix rows hierarchy below Region. In a Power BI matrix visual, placing fields in a hierarchy within the Rows well enables the built-in drill-down/expand feature, letting users go from region to salesperson level directly in the same visual. Drill-through (A) navigates to a separate detail page rather than drilling within the matrix, bookmarks (B) only toggle saved view states and do not create a hierarchy, and tooltips (D) merely display supplemental information on hover without enabling drill-down.

Answer

Set up drill-through from the region to a salesperson detail page.

Answer

Use bookmarks to switch between region and salesperson views.

Answer

Enable tooltips that show salesperson details on hover.

Question 14

You have a Power BI dataset with a fact table containing sales transactions and a dimension table for customers. The customer dimension includes a calculated column that uses the LOOKUPVALUE function to retrieve a customer's region from another table. The report performance is slow. What should you do to improve performance?

Accepted Answer

Remove the LOOKUPVALUE column and instead create a relationship between the tables.. The correct option is C: remove the LOOKUPVALUE calculated column and instead create a relationship between the tables. LOOKUPVALUE is a row-by-row DAX function that forces the formula engine to scan the target table for every row during processing and can also cause expensive query-time evaluations, whereas a proper relationship lets the VertiPaq engine resolve the lookup through the model's relationship graph, which is far more efficient. Since the customer dimension and the other table share a key, a relationship is the native, performant way to propagate the region attribute. Option A is unrelated to DAX performance and concerns Power Query folding behavior, not calculated columns. Option B (incremental refresh) only reduces refresh time and data volume loaded, not the cost of a LOOKUPVALUE column during report queries. Option D (more RAM) may mask memory pressure but does not address the inefficient row-by-row lookup logic.

Answer

Disable the 'Reduce queries sent to the source' option.

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Enable incremental refresh on the fact table.

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Increase the amount of RAM on the Power BI service capacity.

Question 15

You are building a Power BI report to analyze customer churn. You want to add a visual that shows the trend of churn rate over time. Which visual type is most appropriate?

Accepted Answer

Line chart. A line chart is best for showing trends over time. Option B is wrong because a stacked bar chart is better for comparing parts of a whole. Option C is wrong because a scatter plot shows correlation between two variables. Option D is wrong because a pie chart shows proportions at a single point in time.

Answer

Stacked bar chart

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Scatter plot

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Pie chart