Businesses need data to thrive. They scrounge through petabytes of data they are surrounded by to unearth business intelligence. But not everyone in an organization is data-savvy enough to comprehend the information extracted using data.
In short, the critical insights extracted from business data must be communicated to everyone. This is why data visualization is one of the most important aspects of Data Science. As a result, data visualization tools enjoy great demand and are regarded as highly valuable among Data Science skill sets.
Have you laid out your Data Science career roadmap yet? If not, check out this article on the Data Science career roadmap for beginners and find out what other skills you need to stand out in the job market!
Tableau is one of the most popular data visualization tools in the market. Here are the top 25 Tableau interview questions and answers to prepare for your next Data Science interview.
What is Tableau?
Tableau is a robust and rapidly expanding data visualization platform used in the business intelligence sector. It assists in putting raw data into a format that is very simple to interpret. Professionals at all levels of a business can understand the data, thanks to Tableau. It also enables non-technical users to design unique dashboards.
Features of Tableau
- Amazing Visualization
Today, you can work with a lot of unorganized data and create a wide variety of visuals. Thanks to Tableau's built-in features, you can make visualizations that undoubtedly stand out from the crowd.
- Deep insights into the data
Tableau can assist businesses with data analysis in the future without any predetermined objectives. Visualizations allow you to examine the same data from many perspectives. By imagining it differently and constantly adding components for analysis and comparison, you can create "what if" queries and work with the data. These skills are amplified significantly when working with real-time data.
- The user-friendly approach in the Interface
The main advantage of Tableau is its user-friendly approach. It is designed from scratch for those without coding or technical experience. That is, anyone can use the tool without any prerequisite knowledge. As most of the elements in the tool are drag-and-drop, each visualization is simple.
- Working with multiple Data Sources
The world is getting increasingly data-driven; data can come from various sources. As opposed to other business intelligence and analytics tools, Tableau has an advantage - it helps you connect to various data sources, including cloud-based files, non-relational data, data warehouses, data stored on spreadsheets, and so on. Tableau combines various forms of data to assist businesses in creating eye-catching infographics.
- Switching Between Visualizations
With Tableau, it's very easy to add new datasets that are merged with Tableau utilizing shared fields. You also can alternate between various representations to give a broader context.
The following question can help you crack your Tableau interview questions. Today industries are testing knowledge via scenario-based interview questions. Here are a few interview questions and answers to crack the top companies’ interviews. You might also want to read our Data Science Interview questions.
Tableau Interview Questions and Answers
Q1. What is Data Visualization? Why is it important?
Ans. Data visualization is the graphic display of data. Data visualization tools offer an easy approach to observing and analyzing trends, outliers, and patterns in data by utilizing visual elements like charts, graphs, and maps.
Data visualization is so important as it converts messy data and technical information into easily understandable visual aids, even for the non-tech-savvy folks.
Q2. Explain the Tableau design flow.
Ans. Data Source Connection - Connect the various data source to Tableau.
Data View Building - Build the data view and use different joins to the requirement of the business.
Worksheet Creation - Create a worksheet with the different charts that needed for the dashboarding
Dashboard Creation - Build the dashboard to extract different insights into the data
Story Telling - Build the storyboard to tell the various story based on different scenarios.
Q3. How many types of charts are in Tableau?
Ans. There are 12 types of charts in Tableau. Area Chart, Bar Chart, Box and whisker plots, Bullet Charts, Scatter Plots, Pie Chart, Bubble Chart, Line chart, Histogram, highlight Table, Gannt Chart, and Heat Map.
Q4. What is the difference between Traditional Business Intelligence Tools and Tableau?
Ans. Here is the difference between traditional business intelligence tools and Tableau:
- Traditional BI tools' architecture includes hardware restrictions. While there are no dependencies of any kind in Tableau
- typical BI applications rely on sophisticated technologies, while Tableau's dynamic functionality is achieved with basic associative search.
- Traditional business intelligence (BI) solutions do not handle multi-threading, in-memory, or multi-core computing, but Tableau does after integrating complicated technology.
- As for company operations, Traditional BI solutions offer a pre-defined data view while Tableau performs a predictive analysis.
Q4. Explain the difference between .twb and .twbx extensions.
Ans. .twb (tabulae workbook) in an XML Tableau Workbook File. It contains information about sheets, dashboards, and storyboards. This file links the data source file.
.twbx (tableau Packaged workbook) is a package of compressed files. This contains the data source and all the workbooks compressed together (with Images)
Q5. What kind of connections can you make with your dataset?
Ans. There are two types of connections you can make with your dataset. They are Live connection and Extract Connection. Live connection sends data logic, and Extract connection brings data into the memory.
In a Live connection, the data updates itself automatically in the worksheet and dashboard, whereas, Extract helps you build a dashboard very quickly as data is stable.
Q6. What is Mark Card in Tableau?
Ans. The Mark card is used for doing visual analysis in Tableau. You can drag measures and dimensions to the Marks card; this encodes your data with color, size, shape, text, and other properties that add context, detail, and meaning to the marks in the view.
Q7. What is data blending?
Ans. Data blending is the process of integrating different data sources to form a single, new dataset that may then be processed or analyzed and shown visually in a dashboard or other visualization.
Q8. What are the limitations of Tableau?
Ans. Tableau has the following limitations:
- Cost of the software
- Inflexible pricing
- No aftersales support
- Lots of security issues
- Poor BI capabilities
- Embedment Issues
- Lots of training needed
Q9. What is LOD expression?
Ans. LOD expressions, also referred to as the Level Of Detail expressions, let you calculate values at both the data source level and the visualization level. You have even more choice over the degree of granularity you want to compute.
Q10. How can you view underlying SQL Queries in Tableau?
Ans. Here is how you can view underlying SQL Queries in Tableau:
- Go to the Logs folder in 'My Tableau Repository' folder.
- By default, the My Tableau Repository is inside the My Documents folder on Windows or the Documents folder on a Mac.
- If you have a live connection to the data source, check the log.txt and tabprotosrv.txt files.
- If you use an extract, check the hyperd.log (Tableau 10.5 and newer versions) or tdeserver.txt (Tableau 10.4 and older versions) file.
- The tabprotosrv.txt file often has detailed information about queries.
Q11. What is the TDE file?
Ans. A Tableau Data Extract (TDE) is a compressed snapshot of data that is stored on disk and imported into memory when necessary to produce a Tableau viz.
Q12. What are the different Tableau files?
Ans. The different Tableau files are:
- Workbooks (.twb)
- Bookmarks(.tbm)
- Packaged Workbooks(.twbx)
- Extract( .hyper or .tde)
- Data Source (.tds)
- Packaged Data Source(.tdsx)
Q13. Differentiate between Tiled and Floating in dashboards?
Ans. When compared to floating layouts, which enable worksheets to overlap and obscure each other's data when they do, tiled layouts ensure that each worksheet and object is fully visible. This is especially problematic when employing filters because different views will be produced. While tiled layouts display the entirety of each worksheet, including any blank background space, floating layouts allow an end user to hide undesirable blank background space in one worksheet with another worksheet.
Q14. What, according to you, is the difference between published data sources and embedded data sources in Tableau?
Ans. Published data source: It contains connection data that is unrelated to any worksheet and can be used by several workbooks.
Embedded data source: It is linked to a worksheet and has connection details.
Q15. What do you understand about the blended axis?
Ans. This primarily applies to multi-line graphs or charts that use more than two measurements. A blended Axis is another option to consider if it's necessary to display two measurements on the same axis.
Q16. How to perform load testing in Tableau?
Ans. Here is how you perform load testing in Tableau:
- Choose representative workbooks.
- Model the expected usage.
- Think about peak usage.
- Run for at least ten minutes.
- Include think time.
- Stop other work on the server.
Q17. What is Assume Referential integrity?
Ans. Every time a foreign key value is used, it must refer to a legitimate, currently active primary key in the parent database in order to maintain referential integrity. Referential integrity is a concept that guarantees the consistency of relationships between databases and tables. It makes sure that data references are legitimate.
Tableau has an option to Assume Referential Integrity. Data->Data-source->"Assume Referential Integrity
Q18. Can Tableau be installed on MAC OS?
Ans. Yes, Tableau can be installed on MAC OS.
Q19. What is the maximum number of rows Tableau can use at a time?
Ans. Even while Tableau includes petabytes of data, it intelligently uses just those rows and columns that you need to extract for your purpose, so the maximum number of rows or columns is limitless.
Q20. What is a Gantt chart?
Ans. Gantt Chart uses a series of horizontal lines to depict the amount of work done in a certain time period in relation to the amount planned for those periods. Gantt chart lists the tasks on the vertical axis, and the time intervals on the horizontal axis.
Q21. What is VIZQL in Tableau?
Ans. It is the proprietary query language behind the Tableau product suite's visual rendering. It is essentially a translator of SQL queries that traditionally return numbers and tables into an effortless visual analysis.
Q22. How does one create stories in Tableau?
Ans. Follow these steps to create stories in Tableau:
- Click the New Story tab.
- In the lower-left corner of the screen, choose a size for your story. Choose from one of the predefined sizes, or set a custom size in pixels.
- By default, your story gets its title from the sheet name. To edit it, right-click the sheet tab, and choose Rename Sheet.
- To start building your story, double-click a sheet on the left to add it to a story point.
- Click Add a caption to summarize the story point.
- To further highlight the main idea of this story point, you can change a filter or sort on a field in the view. Then save your changes by clicking Update on the story toolbar above the navigator box.
- Add Story to the worksheet.
Q23. Is Tableau software good for strategic acquisition?
Ans. Yes! Of course. It provides you with data understanding to the degree that other technologies cannot. Additionally, it aids in planning, identifying irregularities, and process improvement for the benefit of your business.
Q24. What is a Sankey chart in Tableau?
Ans. Tableau Sankey chart diagrams are a type of visual representation that shows how values flow from one set to another. Links are used to describing connections between nodes, which are connected objects. When you wish to display a many-to-many mapping between two categorical dimensions, Sankeys works well. If you want to avoid using bar charts or pie charts, the Sankey chart in Tableau.
Q25. What is Context Filter Disadvantages?
Ans. In general, Tableau takes a little while to contextualize a filter. The software creates a temporary table for that particular context filter if the filter is set to be a context filter.
Closing Notes
Bear in mind that Tableau is all about how you see the data and how you want to represent the same. If you are looking to prepare for other Data Science interview questions, you might also like to check out this article on Data Science interview questions.
