Power BI Assessment to evaluate data experts

Mercer | Mettl's subject matter experts have designed the Mercer | Mettl Power BI Test to capture a candidate's complete understanding of analyzing and visualizing data.

What is inside this Power BI Test?

It consists of forty MCQs to be completed in fifty minutes. The questions offer insights into the candidate's knowledge of Power BI, SQL, ETL, and data modelling. The Power BI Assessment evaluates these basic, intermediate, and advanced subskills.

What is a Power BI Test?

The Power BI Online Test evaluates individuals' ability to create reports using Power BI. A proficient Power BI developer must accurately configure charts, utilize Power Query to cleanse data, and employ DAX to generate advanced reports.

How does the Power BI Online Test help recruiters?

The Power BI Online Test assists recruiters and hiring managers identify qualified candidates from a pool of resumes, enabling them to make objective hiring decisions. It streamlines the hiring process by reducing the administrative burden of interviewing numerous candidates and saving time by initially shortlisting only qualified candidates.

What skills does the Power BI Online Test cover?

• Power BI  

This Power BI Assessment Test evaluates a candidate's skills in the Power BI dashboard, slicer, data connections, filters, measures, query, DAX, visualizations and reports.  

• SQL  

This Power BI Assessment evaluates SQL skills: queries, joins, tables, merges, and clauses.  

• ETL  

This Power BI Assessment measures ETL's skills: ETL transform, ETL process, ETL load, ETL architecture, and ETL extract.  

• Data modeling  

This assessment evaluates the following skills in data modeling: schemas, data design, OLTP, UML, and ER Models.

Important hiring topics to test candidates on core Power BI

• Connecting to data sources and importing: It involves connecting Power BI to various data sources. Assessing candidates' proficiency in gathering data from different sources is essential for creating insightful Power BI reports.  
• DAX formulas: This skill assesses candidates' knowledge of using DAX language in Power BI for calculations. Measuring this skill ensures candidates can perform complex calculations and aggregations.  
• Data models: This skill involves creating efficient data models in Power BI and defining relationships, hierarchies, and measures. Measuring this skill evaluates candidates' ability to structure data for optimal performance and analysis.  
• Themes and visualization: This skill focuses on applying visual themes and creating visually appealing visualizations in Power BI. Measuring this skill ensures candidates can design meaningful and visually appealing reports.  
• Power BI Desktop: This skill covers candidates' overall proficiency in using Power BI Desktop, including creating reports, managing data connections, and implementing advanced functionalities. Assessing this skill is crucial as Power BI Desktop is a central tool for Power BI development.  
• Interactive reports: This skill measures candidates' proficiency in creating interactive reports, including drill-throughs, bookmarks, and navigation. Testing this skill ensures candidates can create dynamic and user-friendly reports for data exploration.

Sample questions with answers

1. What does Power Pivot do?   

Power Pivot has been an add-on by Microsoft for Excel since 2010. It extends the analytical capabilities and services of Microsoft Excel.

2. What is the purpose of DAX?  

DAX, which stands for Data Analysis Expressions, is a collection of functions, operators, and constants used in formulas to calculate and return values. It helps users create new information from existing data.

3. What does the "GetData" feature in Power BI do?  

The "GetData" feature in Power BI is a simple icon used to import data from a source.

4. When and why would you use a custom visual file in Power BI?  

A custom visual file is used when the prepackaged files do not meet the specific needs of a business. Developers create custom visual files, which can be imported and used like prepackaged files.

5. What are some advantages of using Power BI?  

Power BI offers several advantages, including:  

• Enabling the creation of interactive data visualizations in data centers  
• Allowing users to transform data into visuals and easily share them with others  
• Establishing a connection between Excel queries and dashboards for quick analysis

6. Which types of data sources can Power BI connect to?  

Power BI connects to various data sources, categorized into three main types: files, content packs, and connectors.

7. What does the CALCULATE function do in DAX?  

The CALCULATE function evaluates the sum of the sales amount column in the sales table within a modified filter context. It is the only function that allows users to alter the filter context of measures or tables.

8. Where is data stored in Power BI?  

In most cases, Power BI utilizes the cloud for data storage. It can also use a desktop service. Microsoft Azure, specifically Azure SQL Database and Azure Blob Storage, is the primary cloud service for storing data.

9. What are the different versions of Power BI?  

Power BI has several versions, including Power BI Desktop, Power BI service, and Mobile Power BI apps for iOS and Android devices.

10. What is the function of row-level security in Power BI?  

The function of row-level security is limiting the data that a user can view and access by relying on filters. Users can define roles and rules in Power BI Desktop. They can publish them to Power BI Service to configure row-level security.