Microsoft 70-778: Analyzing and Visualizing Data with Microsoft Power BI — Questions and Answers

Question 1: What is the difference between Power BI Pro and Power BI Premium Per User (PPU)?

Pro is for desktop use; PPU is for cloud use only
PPU includes all Pro features plus advanced capabilities like paginated reports and AI features at the user level (Correct answer)
Pro supports more data sources than PPU
PPU is a group license while Pro is individual

Correct answer: PPU includes all Pro features plus advanced capabilities like paginated reports and AI features at the user level

Premium Per User includes all Power BI Pro capabilities plus premium features like paginated reports, AI visuals, and larger dataset sizes at a per-user cost.

Question 2: What is a common performance drawback of excessive bidirectional cross-filtering in a Power BI data model?

It reduces the number of available DAX functions
It prevents the use of calculated columns
It can create ambiguous filter paths, leading to slower queries and unexpected results (Correct answer)
It forces all tables into DirectQuery mode

Correct answer: It can create ambiguous filter paths, leading to slower queries and unexpected results

Bidirectional cross-filtering multiplies the filter propagation paths the engine must evaluate, causing ambiguity and performance degradation in complex models.

Question 3: What is a KPI visual in Power BI used for?

Comparing multiple measures side by side
Displaying geographic data on a map
Showing a metric against a target or goal with a status indicator (Correct answer)
Filtering report pages

Correct answer: Showing a metric against a target or goal with a status indicator

A KPI visual displays a key metric compared to a defined target, with a trend indicator showing progress direction.

Question 4: What does the HASONEVALUE function return in DAX?

TRUE if the specified column has exactly one value in the current filter context (Correct answer)
The single value in a column if only one exists
The count of unique values in a column
TRUE if a column has no blank values

Correct answer: TRUE if the specified column has exactly one value in the current filter context

HASONEVALUE returns TRUE when the filter context for the specified column results in exactly one distinct value.

Question 5: What does a composite model in Power BI allow you to do?

Combine Import and DirectQuery tables in a single model (Correct answer)
Create models with no relationships
Import data from multiple Excel files only
Run Python scripts in the model

Correct answer: Combine Import and DirectQuery tables in a single model

Composite models allow combining Import mode and DirectQuery mode tables within the same Power BI model.

Question 6: You've uploaded a Microsoft Excel workbook to Microsoft SharePoint Online. Several Power View sheets are included in the workbook. In the Power BI service, you must replicate the Power View sheets into reports. Solution: Get the data from SharePoint Online using the Power BI service, then choose Import. Is this achieving the goal?

Correct (Correct answer)
Incorrect

Correct answer: Correct

To replicate Power View sheets from an Excel workbook into Power BI service reports, the correct approach is to use the 'Get data' feature in the Power BI service. By choosing to 'Import' the Excel workbook from SharePoint Online, Power BI reads the entire workbook, including its data model and any embedded Power View sheets, and automatically creates corresponding datasets and reports in the Power BI service. This method effectively migrates the Power View content.

Question 7: You create a table named Sales from the Home tab in Power BI Desktop by clicking Enter Data. When you add Region and Sales to a visualization, the following data appears. Why are there just four rows of data in the visualization instead of six?

the Data Category of Region
the Data Category of Sales
the Default Summarization on Sales
the Default Summarization on Region (Correct answer)

Correct answer: the Default Summarization on Region

If you have 6 rows of data but a visualization shows only 4 rows for 'Region' and 'Sales', it implies that there are duplicate region entries in your original 6 rows, and the visualization is grouping by distinct regions. While Power BI visuals inherently group categorical data, the 'Default Summarization on Region' being set to 'Count (Distinct)' (or similar aggregation for text fields) would explicitly cause the visual to display only the unique region values, thus reducing the number of displayed rows from the total raw data count.

Question 8: What is Microsoft Purview's role in Power BI governance?

Providing data cataloging, lineage tracking, and sensitivity classification for Power BI assets (Correct answer)
Managing Power BI gateway connections
Running Power BI refresh jobs
Handling Power BI billing and licensing

Correct answer: Providing data cataloging, lineage tracking, and sensitivity classification for Power BI assets

Microsoft Purview integrates with Power BI to catalog assets, track data lineage, and apply sensitivity labels for enterprise data governance.

Question 9: You're working on a Power BI Desktop report with many bar charts and a date slicer, and you need to make a slide show that can be seen via the Power BI service. The charts must be filtered for a different year on each slide. Before you publish the report, what should you do?

Create groups using the Bin group type after configuring page level filters.
Create bookmarks after filtering the bar charts with the slicer (Correct answer)
Select Selection Pane after configuring drillthrough filters for each bar chart
Create groups using the List group type after configuring report level filters

Correct answer: Create bookmarks after filtering the bar charts with the slicer

To create a slideshow where bar charts are filtered for different years on each 'slide' (or view), Power BI bookmarks are the ideal solution. Bookmarks capture the current state of a report page, including all applied filters, slicer selections, and visual configurations. By setting the date slicer to a specific year and then creating a bookmark for that state, you can define multiple views that can then be played sequentially as a slideshow in the Power BI service.

Question 10: What is Power Query used for in Power BI?

Publishing reports to the Power BI Service
Connecting to data sources and transforming data before loading (Correct answer)
Creating visualizations
Writing DAX measures

Correct answer: Connecting to data sources and transforming data before loading

Power Query is the ETL (Extract, Transform, Load) engine in Power BI used to connect, clean, and shape data before analysis.

Question 11: What is dynamic Row-Level Security (RLS) in Power BI?

RLS that uses the logged-in user's identity (via USERNAME() or USERPRINCIPALNAME()) to filter data (Correct answer)
RLS that refreshes hourly to update filter rules
RLS that changes based on slicer selections
RLS applied at the workspace level instead of the dataset

Correct answer: RLS that uses the logged-in user's identity (via USERNAME() or USERPRINCIPALNAME()) to filter data

Dynamic RLS uses DAX functions like USERPRINCIPALNAME() to filter data based on the logged-in user's email address stored in the data model.

Question 12: What does 'Append Queries' do in Power Query?

Merges two tables by matching on a key column
Stacks rows from multiple tables vertically into one table (Correct answer)
Joins two tables side by side
Removes duplicate rows across tables

Correct answer: Stacks rows from multiple tables vertically into one table

Append Queries combines tables by stacking their rows on top of each other, similar to UNION ALL in SQL.

Question 13: What is the purpose of a waterfall chart in Power BI?

Showing correlation between two variables
Displaying cumulative effects of sequential positive and negative values (Correct answer)
Mapping geographic data
Comparing categories side by side

Correct answer: Displaying cumulative effects of sequential positive and negative values

A waterfall chart shows how a series of positive and negative values cumulatively contribute to a final total.

Question 14: What is a 'lineage view' in Power BI Service?

A diagram showing dependencies between data sources, dataflows, datasets, and reports (Correct answer)
A visual showing report page navigation flow
A history log of report edits
A map of user access permissions across workspaces

Correct answer: A diagram showing dependencies between data sources, dataflows, datasets, and reports

Lineage view displays the dependency chain from data sources through dataflows and datasets to reports and dashboards.

Question 15: Which feature in Power BI helps avoid accidental many-to-many relationships when using bidirectional filters?

Composite keys
Single direction filtering (Correct answer)
Assume referential integrity
Row-level security

Correct answer: Single direction filtering

Using single direction filtering prevents unintended filter propagation that can create ambiguous many-to-many join behavior.

Question 16: What is Azure Active Directory (AAD) used for in Power BI?

Managing scheduled refresh for datasets
Storing Power BI datasets in Azure
Generating DAX expressions automatically
Authenticating users and managing access permissions to Power BI resources (Correct answer)

Correct answer: Authenticating users and managing access permissions to Power BI resources

Azure Active Directory handles authentication and authorization for Power BI, controlling who can access what content based on identity.

Question 17: Which DAX function counts the number of rows in a table?

COUNT
COUNTBLANK
COUNTA
COUNTROWS (Correct answer)

Correct answer: COUNTROWS

COUNTROWS returns the number of rows in a specified table or table expression.

Question 18: Which Power BI feature allows end users without Pro licenses to view reports if the workspace is on Premium capacity?

Viewer role assignment
Free license consumption via Premium capacity (Correct answer)
Read-only sharing
Public sharing via embed code

Correct answer: Free license consumption via Premium capacity

Power BI Premium capacity allows free-license users to view reports published to that capacity without requiring individual Pro licenses.

Question 19: What DAX practice best reduces repeated evaluation of the same sub-expression within a complex measure?

Adding more slicers to the report page
Switching the dataset to DirectQuery mode
Using VAR to store intermediate results and reference them multiple times (Correct answer)
Nesting CALCULATE calls more deeply

Correct answer: Using VAR to store intermediate results and reference them multiple times

Declaring a VAR caches the result of an expression so it is evaluated only once; referencing that variable multiple times prevents redundant recalculations by the formula engine.

Question 20: What is the difference between SUM and SUMX in DAX?

SUMX only works with text columns
SUM is faster than SUMX
SUM supports multiple columns; SUMX supports one
SUM works on columns; SUMX iterates a table row by row (Correct answer)

Correct answer: SUM works on columns; SUMX iterates a table row by row

SUM aggregates a single column directly, while SUMX iterates each row of a table and evaluates an expression per row.

Question 21: What is the purpose of 'sensitivity labels' in Power BI?

Labeling measures with business descriptions
Marking reports as draft or final
Classifying and protecting content based on data sensitivity using Microsoft Information Protection (Correct answer)
Adding visual color labels to charts

Correct answer: Classifying and protecting content based on data sensitivity using Microsoft Information Protection

Sensitivity labels classify Power BI content (reports, datasets) by data sensitivity level and can enforce protection like encryption when exported.

Question 22: What does 'Dual' storage mode mean for a table in Power BI?

The table can act as either Import or DirectQuery depending on the query (Correct answer)
The table is stored in two databases
The table has two primary keys
The table exists in both Power BI Desktop and Service

Correct answer: The table can act as either Import or DirectQuery depending on the query

Dual mode allows a table to behave as Import or DirectQuery depending on whether the query requires cached or live data.

Question 23: What language do Power Query transformations use behind the scenes?

DAX
M (Power Query Formula Language) (Correct answer)
Python
SQL

Correct answer: M (Power Query Formula Language)

Power Query uses M language, a functional language that defines every transformation step applied to your data.

Question 24: What is required to enable Scheduled Refresh for an on-premises data source in Power BI?

An on-premises data gateway (Correct answer)
A Power BI Premium license
A direct VPN connection to the server
A service principal with admin rights

Correct answer: An on-premises data gateway

An on-premises data gateway acts as a secure bridge between Power BI Service in the cloud and on-premises data sources.

Question 25: What is static Row-Level Security (RLS) in Power BI?

RLS applied dynamically via DAX username functions
RLS rules with hardcoded filter values that restrict data to fixed categories (Correct answer)
RLS rules that change based on the logged-in user
RLS managed through Active Directory groups only

Correct answer: RLS rules with hardcoded filter values that restrict data to fixed categories

Static RLS uses fixed DAX filter expressions with hardcoded values in role definitions to restrict what data members of that role can see.

Question 26: What is a Power BI dashboard compared to a report?

A dashboard allows data editing; a report is read-only
A dashboard runs in Power BI Desktop; a report runs in the Service
A report is a single visual; a dashboard has many reports
A dashboard is a single-page canvas of pinned visuals from multiple reports; a report can have multiple pages (Correct answer)

Correct answer: A dashboard is a single-page canvas of pinned visuals from multiple reports; a report can have multiple pages

A dashboard is a single-page collection of pinned tiles from reports, while a report is a multi-page interactive document.

Question 27: What is the purpose of a 'Parameter' in Power Query?

A variable value that can be used dynamically within query steps (Correct answer)
A connection string stored securely
A fixed threshold for filtering rows
A column alias for reporting

Correct answer: A variable value that can be used dynamically within query steps

A Power Query Parameter is a reusable variable that can be used in query steps, source paths, or filter conditions.

Question 28: Which Power Query transformation splits a column into multiple columns based on a delimiter?

Extract
Split Column (Correct answer)
Parse
Pivot Column

Correct answer: Split Column

Split Column divides a column into multiple columns using a specified delimiter like a comma, space, or custom character.

Question 29: What does 'Merge Queries' do in Power Query?

Stacks rows from two tables vertically
Removes matching rows from one table
Joins two tables horizontally on a common key column (Correct answer)
Combines all columns from all tables

Correct answer: Joins two tables horizontally on a common key column

Merge Queries performs a join between two tables based on matching key columns, similar to a SQL JOIN.

Question 30: What happens when you set a query's load setting to 'Enable Load' off in Power Query?

The query runs but its results are not loaded into the data model (Correct answer)
The query is deleted from the model
The query is disabled and will not refresh
The query is published to the Power BI Service

Correct answer: The query runs but its results are not loaded into the data model

Disabling 'Enable Load' keeps the query available as a staging or reference query without adding its data to the final model.

Microsoft 70-778: Analyzing and Visualizing Data with Microsoft Power BI

Exam 70-778 validates skills in consuming and transforming data using Power BI Desktop, modeling and visualizing data with DAX, and configuring dashboards, reports, and apps in the Power BI Service. It is part of the MCSA: BI Reporting certification.

Questions

35 min

Time Limit

70%

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