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

Question 1: Which Power BI feature enables governance by allowing admins to enforce policies on workspace creation and sharing?

Power BI Gateway
Power BI Admin Portal (Correct answer)
Power BI Desktop settings
Power BI Embedded

Correct answer: Power BI Admin Portal

The Power BI Admin Portal provides tenant-level settings allowing administrators to control feature access, sharing policies, and workspace governance.

Question 2: What Power BI license is required to share content with external users outside your organization?

Power BI Pro (Correct answer)
Power BI Desktop
Power BI Premium only
Power BI Free

Correct answer: Power BI Pro

Power BI Pro is required for sharing reports and dashboards with other users, including external guests added via Azure AD B2B.

Question 3: Which storage mode in Power BI sends queries directly to the source database without caching data?

Dual
Import
DirectQuery (Correct answer)
Composite

Correct answer: DirectQuery

DirectQuery mode sends every query directly to the data source, ensuring real-time data without local caching.

Question 4: Which Power BI 'Dual' storage mode behavior best describes how a table operates at query time?

It acts as Import when queried with Import tables and as DirectQuery when queried with DirectQuery tables (Correct answer)
It caches DirectQuery results and serves them from cache for one hour
It simultaneously writes data to two storage locations for redundancy
It duplicates the table as both a fact and a dimension

Correct answer: It acts as Import when queried with Import tables and as DirectQuery when queried with DirectQuery tables

Dual mode allows a single table to behave as Import when joined with other Import tables (for speed) and as DirectQuery when joined with DirectQuery tables (for consistency).

Question 5: Which Power BI Service feature sends automatic email alerts when a dashboard KPI crosses a threshold?

Scheduled refresh
Push notifications
Data alerts (Correct answer)
Subscriptions

Correct answer: Data alerts

Data alerts in Power BI Service send email notifications when a dashboard tile's value goes above or below a defined threshold.

Question 6: What is a calculated column in Power BI?

A column from a live database view
A column imported from a CSV file
A column created in Power Query
A column computed during query refresh using DAX (Correct answer)

Correct answer: A column computed during query refresh using DAX

A calculated column uses a DAX expression evaluated row-by-row and stored in the model during data refresh.

Question 7: What does 'Merge Queries' do in Power Query?

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

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 8: What does the ALL() function do when used inside CALCULATE?

Removes all filters from the specified table or columns (Correct answer)
Adds new filters to the context
Returns all values from a column as a list
Applies all existing filters

Correct answer: Removes all filters from the specified table or columns

ALL() removes filters from the specified table or columns, allowing calculations to ignore slicers and report filters.

Question 9: What does the DAX function CALCULATE do?

Evaluates an expression in a modified filter context (Correct answer)
Sums values in a column
Returns the first value in a column
Counts rows in a table

Correct answer: Evaluates an expression in a modified filter context

CALCULATE evaluates a DAX expression after applying the specified filter modifications to the current filter context.

Question 10: Which Power BI storage mode loads all data into the in-memory VertiPaq engine for the fastest query performance?

DirectQuery
Import (Correct answer)
Composite
Live Connection

Correct answer: Import

Import mode physically copies data into Power BI's in-memory VertiPaq engine, enabling the fastest query performance since no source queries are needed at report time.

Question 11: Which DAX function returns the total of all values in a column, ignoring any filters?

CALCULATE(SUM(), ALL()) (Correct answer)
TOTALSUM
SUM
SUMX

Correct answer: CALCULATE(SUM(), ALL())

Wrapping SUM with CALCULATE and ALL() removes all filters, returning the grand total regardless of current context.

Question 12: What is Power BI Embedded?

A way to embed SQL queries inside Power BI reports
A feature that embeds Excel tables into Power BI reports
A service for embedding Power BI reports and dashboards into custom applications for external users (Correct answer)
A way to embed Power BI Desktop into SharePoint

Correct answer: A service for embedding Power BI reports and dashboards into custom applications for external users

Power BI Embedded allows ISVs and developers to integrate Power BI visuals into their own applications for end users who may not have Power BI licenses.

Question 13: In DAX Studio's Server Timings pane, what does a disproportionately high Formula Engine (FE) time relative to Storage Engine (SE) time typically indicate?

The data source connection is slow
The DAX contains complex iterating logic the storage engine cannot fully handle (Correct answer)
The dataset exceeds the Power BI Pro size limit
The report has too many visuals on one page

Correct answer: The DAX contains complex iterating logic the storage engine cannot fully handle

High FE time indicates the DAX uses operations like row-by-row iteration (SUMX, FILTER) that the VertiPaq storage engine cannot satisfy with a simple column scan, requiring more formula engine cycles.

Question 14: What is dynamic Row-Level Security (RLS) in Power BI?

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

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 15: What is the Advanced Editor in Power Query used for?

Running SQL queries against the data source
Configuring scheduled refresh settings
Setting up row-level security rules
Viewing and editing the full M code for a query (Correct answer)

Correct answer: Viewing and editing the full M code for a query

The Advanced Editor displays the complete M language script for a query, allowing direct code editing of all transformation steps.

Question 16: What Power BI feature allows you to test which data a specific user or role would see under RLS?

Role simulator in Power BI Service
Gateway role tester
'View as role' in Power BI Desktop or Service (Correct answer)
DAX security debugger

Correct answer: 'View as role' in Power BI Desktop or Service

'View as role' lets you preview the report as if you were a member of a specific RLS role, verifying that filters are applied correctly.

Question 17: You have ten dashboards in your workplace. Sales Data is a dashboard that shows data from two sources. You realize that users can't find what they're looking for. Natural language queries are used to populate the dashboard with data. You must ensure that consumers may utilize natural language searches to find data. What are your options?

Modify the Language Settings in the workspace's settings
Set the Sales Data dashboard as a Favorite from the dashboard menu
Modify the Q&A and Cortana settings in the datasets' properties (Correct answer)
Modify the Q&A settings in the dashboard's properties

Correct answer: Modify the Q&A and Cortana settings in the datasets' properties

Natural language queries (Q&A) in Power BI rely heavily on the underlying dataset for accurate responses. To ensure users can effectively find data using Q&A, you must modify the Q&A and Cortana settings within the properties of the relevant datasets. These settings allow you to define synonyms, suggest questions, and configure field properties, all of which enhance the Q&A engine's ability to understand and respond to user queries.

Question 18: What does a composite model in Power BI allow you to do?

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

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

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

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 20: What is the function of 'Bookmarks' in Power BI?

Scheduling report refresh
Pinning visuals to a dashboard
Saving favorite data sources
Capturing the current state of a report page for navigation or storytelling (Correct answer)

Correct answer: Capturing the current state of a report page for navigation or storytelling

Bookmarks save the current state of a report page (filters, slicers, visibility) and can be used for navigation or storytelling.

Question 21: What is the purpose of a measure in Power BI?

To store a static value in a table
To define table relationships
To calculate aggregated values dynamically based on filter context (Correct answer)
To set row-level security rules

Correct answer: To calculate aggregated values dynamically based on filter context

Measures are DAX calculations that evaluate dynamically based on the filters and context applied in a report.

Question 22: What is the purpose of the DIVIDE function in DAX?

Converts a fraction to a percentage
Divides two numbers safely, returning an alternate result if denominator is zero (Correct answer)
Divides two numbers and returns an error if denominator is zero
Rounds a division result to two decimal places

Correct answer: Divides two numbers safely, returning an alternate result if denominator is zero

DIVIDE safely handles division by zero by returning an optional alternate result instead of throwing an error.

Question 23: Which Power BI feature allows you to show different visuals based on a user's selection using buttons?

Drill-through
Conditional formatting
Page navigation
Bookmarks with buttons (Correct answer)

Correct answer: Bookmarks with buttons

Combining bookmarks with buttons allows you to create toggle effects that show and hide different visuals based on user interaction.

Question 24: 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 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
Create groups using the Bin group type after configuring page 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 25: In Power BI, which view allows you to see the raw data stored in each table?

Data view (Correct answer)
Query editor
Model view
Report view

Correct answer: Data view

Data view displays the actual rows and columns of data stored in each table of your Power BI model.

Question 26: What does 'Append Queries' do in Power Query?

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

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 27: What is query folding in Power Query?

Hiding intermediate query steps from the applied steps pane
Pushing transformation steps back to the data source to execute natively (Correct answer)
Combining queries from different workspaces
Collapsing multiple queries into one for performance

Correct answer: Pushing transformation steps back to the data source to execute natively

Query folding allows Power Query to translate transformation steps into native source queries (e.g., SQL), improving performance by reducing data transferred.

Question 28: Which Power Query step removes rows where a specified column's value is null?

Filter Rows (Correct answer)
Remove Duplicates
Remove Errors
Fill Down

Correct answer: Filter Rows

Filter Rows allows you to filter out rows based on conditions, including removing rows where a column value is null.

Question 29: What is the purpose of a 'decomposition tree' visual in Power BI?

Showing hierarchical relationships in an organizational chart
Mapping parent-child database relationships
Displaying decision tree logic for AI models
Interactively breaking down a measure across multiple dimensions (Correct answer)

Correct answer: Interactively breaking down a measure across multiple dimensions

The decomposition tree visual lets users interactively split a measure by different dimensions to understand root causes or contributions.

Question 30: What is the Power BI REST API used for?

Connecting Power BI to REST-based data sources only
Exporting reports as REST-compliant formats
Programmatically managing Power BI resources like workspaces, datasets, and reports (Correct answer)
Writing DAX queries from outside Power BI

Correct answer: Programmatically managing Power BI resources like workspaces, datasets, and reports

The Power BI REST API allows developers to automate and manage Power BI assets including embedding, refreshing datasets, and managing workspaces.

Question 31: What is a 'dataflow' in Power BI?

A data pipeline from Azure Data Factory
A data export workflow to SharePoint
A reusable set of Power Query transformations stored in the Power BI Service (Correct answer)
A real-time data stream from IoT devices

Correct answer: A reusable set of Power Query transformations stored in the Power BI Service

Dataflows store reusable Power Query ETL logic in the cloud, allowing multiple datasets and reports to share the same transformation logic.

Question 32: Which relationship cardinality is most common in a star schema Power BI model?

Many-to-many
One-to-many (Correct answer)
One-to-one
Many-to-one

Correct answer: One-to-many

One-to-many is the most common cardinality, where one dimension row relates to many fact table rows.

Question 33: What is cross-filtering in Power BI reports?

Applying the same filter to multiple report pages
When selecting a data point in one visual automatically filters other visuals on the same page (Correct answer)
Filtering data in Power Query
Filtering across multiple data sources

Correct answer: When selecting a data point in one visual automatically filters other visuals on the same page

Cross-filtering occurs when clicking a data point in one visual filters the data displayed in other connected visuals on the report page.

Question 34: Which data type in Power Query stores whole numbers without decimal places?

Decimal Number
Fixed Decimal Number
Whole Number (Correct answer)
Text

Correct answer: Whole Number

Whole Number data type in Power Query stores integers (positive and negative whole numbers) without any decimal precision.

Question 35: What does enabling 'Export to Excel' in Power BI tenant settings allow users to do?

Automatically sync Power BI datasets with Excel workbooks
Download underlying data from Power BI visuals into Excel spreadsheets (Correct answer)
Export .pbix files to Excel format
Publish Excel files to Power BI Service

Correct answer: Download underlying data from Power BI visuals into Excel spreadsheets

When enabled, this setting permits report consumers to export the data behind Power BI visuals into Excel files.

Question 36: The visualization in the following display is available to you. The values must be displayed as shown in the following exhibit. What are your options?

Change the Data Type to Percentage in the data source's query
Create a metric that includes the percent sign in the values (Correct answer)
Change the Data Type to Percentage under the Modeling tab
Create a calculated column in which the numbers are multiplied by the percent symbol

Correct answer: Create a metric that includes the percent sign in the values

When displaying values as percentages, especially if the raw data is not already in a decimal format (e.g., 0.5 for 50%), creating a measure (metric) provides the most control. A measure can perform necessary calculations (like dividing by 100 if the raw data is '50' for 50%) and then apply specific formatting to ensure the percent sign is correctly included in the displayed value. While changing the data type to Percentage (Option D) works for decimal values, a metric offers greater flexibility for various data inputs and precise display requirements.

Question 37: 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 38: What is a 'Reference' query in Power Query?

A query that stores credentials for data sources
A query that uses another query as its source without duplicating the data load (Correct answer)
A query that references an external API
A query that imports data from a reference table

Correct answer: A query that uses another query as its source without duplicating the data load

A Reference query points to another query as its starting point, sharing the same data load without running the source query twice.

Question 39: What does the 'Pivot Column' transformation do in Power Query?

Rotates rows into columns based on a key column
Converts attribute-value rows into separate columns (Correct answer)
Converts a column to a different data type
Aggregates a column into a single value

Correct answer: Converts attribute-value rows into separate columns

Pivot Column turns unique values from one column into new column headers, essentially transposing key-value pairs into a wide table.

Question 40: You have a Power BI dashboard that shows several sales representations for your company. On the dashboard, you enable Q&A. When using Q&A, you should present users with sample questions to ask. From the Power BI Settings, which settings should you change?

Dashboards
Subscriptions
Datasets (Correct answer)
Workbooks

Correct answer: Datasets

The Q&A feature in Power BI is powered by the underlying datasets that feed the dashboard. To present users with sample questions and improve the overall Q&A experience, you need to configure these settings at the dataset level. Within the dataset's properties in the Power BI service, you can define suggested questions, add synonyms, and manage other Q&A-related options to guide users in their natural language queries.

Question 41: What is a 'tenant setting' in the Power BI Admin Portal?

An organization-wide configuration that enables or restricts Power BI features for all users in the tenant (Correct answer)
A gateway configuration for each data source
A per-user privacy setting
A dataset-level setting for each report creator

Correct answer: An organization-wide configuration that enables or restricts Power BI features for all users in the tenant

Tenant settings in the Admin Portal control which Power BI features are available across the entire organization or to specific security groups.

Question 42: Which Power BI feature allows end users without Pro licenses to view reports if the workspace is on Premium capacity?

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

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

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

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

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 45: Which Power BI Service feature allows users to subscribe to a report page and receive it via email on a schedule?

Push reports
Scheduled export
Data alerts
Email subscriptions (Correct answer)

Correct answer: Email subscriptions

Email subscriptions in Power BI Service send a snapshot of a report page or dashboard to subscribers on a defined schedule.

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.

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120 min

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70%

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