Boost your Power BI knowledge with this quiz focused on key concepts in data modeling, DAX functions, and visualization best practices. Ideal for those preparing for Power BI interview questions, this quiz covers foundational skills in business intelligence and data analytics.
Which of the following is NOT a core component of the Power BI platform used for creating and sharing reports?
Explanation: Power BI Studio is not a component of the Power BI ecosystem. Power BI Desktop is used for report creation, Power BI Service is a cloud-based platform for sharing and collaboration, and Power BI Mobile allows users to access reports on mobile devices. 'Power BI Studio' does not exist as an official product, making it the incorrect option.
In Power BI, what mode allows large datasets to be stored directly in-memory for quick querying and visuals?
Explanation: Import Mode loads data into Power BI's in-memory storage, providing fast performance. DirectQuery and Live Connection work by connecting directly to the data source, often resulting in slower performance for large data. Static Mode is not a recognized feature, making Import Mode the best choice for quick queries and visuals.
Which DAX function is commonly used to create calculated columns or measures that sum values, such as total sales?
Explanation: The SUM function totals values in a column, often used for creating measures like total sales. FILTER refines data sets, COUNTROWS counts the number of rows, and LOOKUPVALUE retrieves values from related tables. Only SUM directly performs addition.
Suppose you have two tables, Products and Sales. What feature in Power BI is used to link them using a common field like 'ProductID'?
Explanation: A Data Relationship connects tables using a key like 'ProductID', enabling combined analysis. Page Filters affect visual displays, Bookmarks save report states, and Measures are calculations, none of which link tables directly.
Which visualization type in Power BI best displays the proportion of sales by region as slices of a whole?
Explanation: A Pie Chart is ideal for illustrating proportions of a total, such as sales by region. Line Charts show trends over time, Scatter Plots display relationships between variables, and Card Visualizations present single values. Only the Pie Chart divides data into parts of a whole.
What is the purpose of a 'Slicer' in a Power BI report dashboard?
Explanation: A Slicer allows users to interactively filter visuals on a report, making it easier to focus on relevant data segments. Data Importing is managed elsewhere, Design Formatting adjusts visual appearance, and Data Refreshing updates the data. Only Interactive Filtering matches the slicer's function.
Which action typically helps improve Power BI report performance for large datasets?
Explanation: Reducing the number of visuals lessens the load on Power BI, improving performance. Increasing file size or using many calculated columns can slow down reports, and disabling the data model is not a valid option. Fewer visuals result in more responsive dashboards.
In Power BI, what is the main role of Power Query during data preparation?
Explanation: Power Query is mainly used to transform and clean data before it enters the data model. Publishing and dashboard creation take place later, and DAX calculations focus on analytical expressions. Only transforming and cleaning are performed directly in Power Query.
Which DAX function changes the filter context of a calculation, for example when calculating total sales for a selected year?
Explanation: CALCULATE adjusts the filter context to produce results based on specific criteria, such as year or category. SUMMARIZE creates summary tables, AVERAGE computes a mean, and REMOVEFILTERS clears all filters but does not apply new ones, making CALCULATE the correct answer.
When building a data model in Power BI, what is the recommended schema structure for efficiency and scalability?
Explanation: Star Schema structures, with fact and dimension tables, support efficient queries and scalability. Circular Schema is not a recognized term, Flat Files lack relational integrity, and Text Tables are primarily for raw data. Star Schema remains the industry best-practice.