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

Question 1: Which Power BI visual type is best suited for showing trends over time?

Pie chart
Funnel chart
Treemap
Line chart (Correct answer)

Correct answer: Line chart

Line charts display data points connected across a continuous axis, making them ideal for showing trends or changes over time.

Question 2: What is a 'certified' dataset in Power BI?

A dataset connected to a government-certified source
A dataset that has been encrypted by Microsoft
A dataset with a valid SSL certificate
A dataset that has been reviewed and endorsed by a designated authority as a trusted data source (Correct answer)

Correct answer: A dataset that has been reviewed and endorsed by a designated authority as a trusted data source

Certified datasets have been vetted and promoted by a Power BI admin or authorized user as a reliable, authoritative data source.

Question 3: Which Power Query step removes rows where a specified column's value is null?

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

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

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

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.

Question 5: 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 6: Which DAX function creates a virtual table by filtering an existing table based on a condition?

SELECTCOLUMNS
FILTER (Correct answer)
SUMMARIZE
CALCULATE

Correct answer: FILTER

FILTER returns a table that is a subset of another table, keeping only rows that satisfy the specified condition.

Question 7: What does the DAX function CALCULATE do?

Sums values in a column
Returns the first value in a column
Evaluates an expression in a modified filter context (Correct answer)
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 8: What is the purpose of 'Scheduled Refresh' in Power BI Service?

Re-publishes the report file daily
Refreshes the browser page on a timer
Automatically updates an imported dataset by re-running the data load from the source on a schedule (Correct answer)
Automatically re-renders visuals every hour

Correct answer: Automatically updates an imported dataset by re-running the data load from the source on a schedule

Scheduled Refresh keeps imported datasets up to date by automatically pulling fresh data from the source at specified intervals.

Question 9: What is a Power BI workspace?

A Power BI Desktop layout view
A database schema used by Power BI
A collaborative container in the Power BI Service for organizing reports, dashboards, and datasets (Correct answer)
A local folder for storing .pbix files

Correct answer: A collaborative container in the Power BI Service for organizing reports, dashboards, and datasets

A workspace in the Power BI Service is a shared environment where teams can collaborate on reports, dashboards, and datasets.

Question 10: 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)
Publish Excel files to Power BI Service
Export .pbix files to Excel format

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 11: 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
Read-only sharing
Viewer role assignment

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 12: What is the role of a bridge table in Power BI data modeling?

To define row-level security
To store calculated measures
To store KPIs and targets
To resolve many-to-many relationships between two tables (Correct answer)

Correct answer: To resolve many-to-many relationships between two tables

A bridge table sits between two tables with a many-to-many relationship, resolving it into two one-to-many relationships.

Question 13: What does 'Merge Queries' do in Power Query?

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

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

Extract
Parse
Split Column (Correct answer)
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 15: What does 'Promote Headers' do in Power Query?

Renames all column headers to uppercase
Adds a new header row to the data
Copies header names from another query
Uses the first row of data as the column headers (Correct answer)

Correct answer: Uses the first row of data as the column headers

Promote Headers takes the first row of the dataset and converts it into the column header names.

Question 16: What does 'Remove Duplicates' do in Power Query when applied to a column?

Removes all rows where any column has a duplicate value
Highlights duplicate rows without removing them
Replaces duplicate values with null
Keeps only the first occurrence of each unique value in the selected column, removing subsequent duplicates (Correct answer)

Correct answer: Keeps only the first occurrence of each unique value in the selected column, removing subsequent duplicates

Remove Duplicates on a column retains the first occurrence of each unique value and deletes all subsequent duplicate rows.

Question 17: In Power BI, what is a 'role-playing dimension'?

A dimension table used for user access control
A single dimension table used multiple times with different relationships (Correct answer)
A dimension that stores user role names
A dimension that drives row-level security

Correct answer: A single dimension table used multiple times with different relationships

A role-playing dimension is a single table (e.g., a Date table) connected to a fact table multiple times via inactive relationships.

Question 18: For Power BI, you'll need to make a customized visualization. What do you think should be the first thing you install?

Microsoft.NET
jQuery
Node.js (Correct answer)
Microsoft Azure PowerShell

Correct answer: Node.js

Developing custom visualizations for Power BI requires a specific development environment. The Power BI Custom Visuals SDK, which is essential for creating these visualizations, relies on Node.js and its package manager, npm. Therefore, installing Node.js is the foundational step and the first thing you need to set up before you can begin developing custom visuals.

Question 19: What Power BI feature allows you to group numerical data into ranges for analysis?

Binning (Correct answer)
Clustering
Partitioning
Bucketing

Correct answer: Binning

Binning in Power BI groups continuous numerical data into defined ranges (bins) to simplify distribution analysis.

Question 20: What is the Advanced Editor in Power Query used for?

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

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 21: You have an app workspace with a report in it. The report contains confidential information. You must verify that the report can be embedded into a bespoke application that will be used by external users. There will be no Microsoft Azure Active Directory user accounts or Power BI licenses for external users. Solution: Purchase Power BI Premium P1 and set up the app workspace to operate in dedicated mode. Is this achieving the goal?

Incorrect
Correct (Correct answer)

Correct answer: Correct

Embedding Power BI content for external users who do not have Power BI licenses or Azure Active Directory accounts requires Power BI Premium capacity. Purchasing Power BI Premium P1 and configuring the app workspace to operate in dedicated mode enables 'Embed for your customers' scenarios. This allows the bespoke application to authenticate and display the report without requiring individual user licenses, as the Premium capacity handles the rendering and sharing.

Question 22: What does 'Append Queries' do in Power Query?

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

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 23: What is the purpose of the 'Viewer' role in a Power BI workspace?

Can create and publish reports in the workspace
Can export data from all datasets in the workspace
Can view and interact with reports and dashboards but cannot edit or publish (Correct answer)
Can manage workspace settings and member access

Correct answer: Can view and interact with reports and dashboards but cannot edit or publish

Viewers can consume (read and interact with) reports and dashboards but have no editing, publishing, or administrative capabilities.

Question 24: What is the purpose of a waterfall chart in Power BI?

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

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 25: What are the three workspace roles in Power BI Service?

Owner, Editor, Reader
Admin, Member, Contributor, Viewer (Correct answer)
Admin, Contributor, Viewer
Owner, Contributor, Consumer

Correct answer: Admin, Member, Contributor, Viewer

Power BI workspaces have four roles: Admin, Member, Contributor, and Viewer, each with different levels of access.

Question 26: What does a slicer do in Power BI?

Provides an on-canvas filter that lets report users interactively filter visuals (Correct answer)
Removes rows from the data model
Splits a visual into multiple panels
Creates a new calculated column

Correct answer: Provides an on-canvas filter that lets report users interactively filter visuals

A slicer is a visual filter element that report users can interact with to filter all connected visuals on the page.

Question 27: What language do Power Query transformations use behind the scenes?

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

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 28: What does the Power BI Admin Portal allow tenant administrators to manage?

Tenant-wide settings, user permissions, audit logs, and feature controls (Correct answer)
Power BI Desktop installation on client machines
Individual report designs and DAX expressions
Gateway configuration for each dataset individually

Correct answer: Tenant-wide settings, user permissions, audit logs, and feature controls

The Admin Portal gives Power BI tenant admins control over organization-wide settings, including export controls, sharing policies, and audit logs.

Question 29: What is the purpose of a measure in Power BI?

To calculate aggregated values dynamically based on filter context (Correct answer)
To define table relationships
To store a static value in a table
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 30: What is a report tooltip in Power BI?

A filter applied only to a specific visual
A legend that appears at the bottom of a visual
A hover-over display that shows additional information about a data point (Correct answer)
A text box that appears on the report canvas permanently

Correct answer: A hover-over display that shows additional information about a data point

A report tooltip is a custom or default popup that appears when a user hovers over a visual, showing additional data context.

Question 31: What is required to enable Scheduled Refresh for an on-premises data source in Power BI?

A Power BI Premium license
A direct VPN connection to the server
A service principal with admin rights
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 32: In Power BI Desktop, you have two queries: Query1 retrieves a table named SMB Customers from a Microsoft SQL Server database, while Query2 retrieves a table named Enterprise Customers from an Oracle database. Both tables have the identical columns. The data from SMB Customers and Enterprise Customers must be combined. Which command do you need to use?

Merge Columns
Append Queries (Correct answer)
Merge Queries
Combine Files

Correct answer: Append Queries

When you have two or more tables with identical columns and you need to combine their rows vertically into a single table, the 'Append Queries' command in Power Query (Query Editor) is the appropriate tool. This operation stacks the data from one query on top of another, consolidating all the customer records from both SMB and Enterprise sources into a unified dataset. 'Merge Queries,' in contrast, combines tables horizontally based on matching column values.

Question 33: Which DAX function counts the number of rows in a table?

COUNTA
COUNTBLANK
COUNTROWS (Correct answer)
COUNT

Correct answer: COUNTROWS

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

Question 34: What does 'Conditional Formatting' in Power BI allow you to do?

Change visual colors, icons, or background based on data values or measures (Correct answer)
Create conditional DAX expressions
Format the M code in Power Query
Apply filters based on conditions in the data model

Correct answer: Change visual colors, icons, or background based on data values or measures

Conditional formatting lets you dynamically apply colors, data bars, icons, or web URLs to table and matrix cells based on their values.

Question 35: What is the purpose of the 'Unpivot Columns' transformation in Power Query?

Converts multiple columns into attribute-value row pairs (Correct answer)
Removes selected columns from a table
Transposes rows and columns
Converts row data into column headers

Correct answer: Converts multiple columns into attribute-value row pairs

Unpivot Columns rotates selected columns into rows, creating an attribute column and a value column for each combination.

Question 36: Which Power BI Service feature allows users to subscribe to a report page and receive it via email on a schedule?

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

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.

Question 37: 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 38: What does 'deployment pipelines' in Power BI help you manage?

Distributing apps to end users
Scheduling data refresh pipelines
Managing gateway connections across environments
CI/CD workflows for promoting Power BI content from development to test to production (Correct answer)

Correct answer: CI/CD workflows for promoting Power BI content from development to test to production

Deployment pipelines provide a structured way to promote Power BI content (reports, datasets) through development, test, and production stages.

Question 39: What is the difference between Power BI Pro and Power BI Premium Per User (PPU)?

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
Pro is for desktop use; PPU is for cloud use only
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 40: What does the 'Group By' transformation do in Power Query?

Sorts rows by a specified column
Splits one column into multiple columns
Aggregates rows based on one or more grouping columns (Correct answer)
Filters rows by a category value

Correct answer: Aggregates rows based on one or more grouping columns

Group By in Power Query aggregates data by specified columns, similar to GROUP BY in SQL.

Question 41: 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 can create ambiguous filter paths, leading to slower queries and unexpected results (Correct answer)
It forces all tables into DirectQuery mode
It prevents the use of calculated columns

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

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

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

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

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 44: You are importing sales data into Power BI Desktop from a Microsoft Excel file named Sales.xlsx. You need to create a bar chart that shows the total sales amount by region. When you create the bar chart, the regions appear as expected, but the sales amount value displays the count of sales amount instead of the sum of sales amount each region. You must modify the query to ensure that the data appears correctly. What are your options?

Add a calculated column to Query Editor that totals the sales amount column. (Correct answer)
Remove the query, then import the data into Microsoft SQL Server.
Change the sales amount column's data type to Numeri
Refresh the data model

Correct answer: Add a calculated column to Query Editor that totals the sales amount column.

When a sales amount column displays a count instead of a sum in Power BI, it often indicates that the column's data type is not numeric, causing Power BI to default to counting non-numeric entries. While changing the data type directly is a common fix, if the column contains mixed data or requires complex parsing (e.g., extracting numbers from text), adding a calculated column in the Query Editor (Power Query) is a robust solution. This new column can be designed to correctly extract and convert sales values into a clean numeric format, ensuring it can be accurately summed in visualizations.

Question 45: In Power BI, which relationship filter direction allows filters to propagate in both directions between two tables?

Bidirectional (Correct answer)
Cross-filter
Unidirectional
Single

Correct answer: Bidirectional

Bidirectional cross-filter direction allows filters to flow from either table to the other in a relationship.

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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