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Job-oriented data visualization with Tableau interview questions & answers

Job-oriented data visualization with Tableau interview questions & answers

A data visualizer is tasked with helping to make sense of heaps and heaps of data that get generated in the course of a business analysis. The job of a data visualizer is to help businesses use data to get thorough and proper direction on what to do with them. In doing this, the data visualizer is required to use both her analytical and creative abilities. While the analytical abilities come into play in having the nous to understand the data; the creative side is used to prepare graphs, pictorials, pie charts, word clouds, infographics, bubble charts, and other interactive visual aids such as dials, gauges and heat maps to make the data interesting and attractive. At the core, data visualizers bring data to life and make them story-like. This is the essence of data visualization. This requires data visualizers to not only be sharp at understanding the import of the data, but to also put them in such a manner that they are interesting, entertaining and insightful.

What do you understand by data visualization?

Answer: 

In simple terms, it is the method of analyzing data and presenting them in a pictorial form through the use of visual aids.

1.    What is the role of Tableau in data visualization?

Answer: 

This is the software program on which data is visualized. Tableau is to data visualization what a racquet is to tennis. It is as central and indispensable as that. No matter where your data is located; it is refined and presented as visual data through Tableau.

2.    Explain Depth Cueing in Visualization

Answer:

Depth cueing is identifying the basic issue for visualization techniques. For example, it is common to find a few 3D objects without depth information, surface identification, or visible line. Depth cueing in such instances addresses such an issue by highlighting the visible lines and displaying visible lines as dashed lines after removing the invisible lines.

3.    What is Informational Visualization?

Answer:

Information visualization uses computer-supported tools to help understand large amount of abstract data. The User Interface Research Group at Xerox PARC, which included Dr. Jock Mackinlay, is credited with having used the term "information visualization" for the first time. Applying information visualization in computer programs means having to select, transform and represent abstract data in a form that humans can easily relate to. The dynamics of visual representation and the interactivity are the two important aspects of information visualization.

4.     Explain Depth Sorting Method in Visualization

Answer:

Also referred to as painter’s algorithm, depth sorting method has the following characteristics:

  • It consists of both image and object space operations
  • It performs the basic function of data visualization
  • In depth sorting method, the surface is sorted in order of decreasing depth
  • In this method, the surface is scan converted in order, starting with the surface of greatest depth
  • It is test listed in the order of increasing difficulty
  • In depth sorting, the surfaces do not overlap.
  • There is also no overlapping of the projections of the two surfaces on to the view plane.

5.    Explain what non-emissive is in Visualization?

Answer:

These are optical effects with which the sunlight or light is converted from any other source to graphic form. An example that comes to mind is liquid crystal display.

6.    What Is Scan Code?

Answer:

This is how one understands a scan code: whenever a key on the keyboard is pressed, the keyboard controller places a code carry to the key that is pressed into a part of the memory that is called the keyboard buffer.

7.    Define disaggregation and aggregation of data

Answer:

Aggregation is the parameter that displays aggregate data, for example the color or brand of a product in a retail store and the sale of units made. To aggregate, one needs to drag the color of the product on the rows to get the sum (total units) of each brand and the price of the product. Choose unit price option – choose measure types as “Avg.”

Disaggregation, on the other hand, is used to display and give understanding of each and every transaction concerning the product.

8.    What is the highest number of tables we can join in Tableau?

Answer:

32 tables.

9.    How do you distinguish between heat map and tree map?

Answer:

A heat map is a wonderful method of comparing categories with size and color and can be used to compare two different measures. A tree map, on the other hand, is a very potent visualization with which the hierarchical (tree–structured) data and part–to–whole relationships can be understood with greater clarity.

10.How is Tableau software useful?

Answer:

Tableau is unimaginably inexpensive compared to most other BI tools. It comes with a free offering (Tableau Public) and another one for academic distribution, which is also free.

It is very easy to use and is very agile, a fact attested by none lesser than Forrester.

It is easy to learn and experiment with.

However, one drawback, if one may consider it so, of Tableau is that it is not a complete technology stack. If heavier tasks such as handling high enterprise data ETL, maintenance, and storage, etc. are needed, other platforms need to be deployed.

 11.Can we do testing in Tableau?

Answer:

No, since it is a data visualization software.

12.What is the method of creating cascading filters without context filter?

Answer:

Let us say we want to create filters for US and its States: we can have filter 1 and filter2, wherein filter I can be the country and filter 2 the States. If we have chosen US, filter 1 will be the country and filter 2, the 50 states. You can choose option 2 to display American states.

Choose options of Filter2 states: select option of “Only relevant values “.

13.What is the method of displaying top 5 and last 5 sales in the same view?

Answer:

This can be done using filters or calculated fields.

14.How is custom color added to Tableau?

Answer:

Create Custom Color code in “Preferences.tps”

Navigation: Documents » My Table Repository »Preferences.tps

Add custom color code

Tableau 9.0 version comes with the color picker option.

15.How does Tableau perform when it has to deal with large datasets?

Answer:

The one thing to remember about Tableau is that its performance is based on the performance of data source. If the data source takes more time to execute a query, then Tableau has no option other than to wait up to that time.

16.Define page shelf

Answer:

This is a prominent feature of Tableau with which the display of output as well as printed results of output can be controlled.

17.What is Tableau Desktop?

Answer:

Considered a landmark technology that was based on technology from Stanford University; Tableau Desktop offers the user the feature of dragging and dropping to analyze data. This simple additional feature can make data visualization an extremely attractive tool. With the Tableau Desktop, the user can connect to data in a few clicks, give it her own visualization, and can create interactive dashboards.

18.What is Tableau Server?

Answer:

A browser- and mobile-based insight meant for anyone to use; Tableau Server can be used to publish dashboards with Tableau Desktop and share them throughout the organization. It is very easy to both set up and run.

19.Describe Tableau Software?

Answer:

Tableau is a BI software with which one can make raw data a lot more meaningful and interesting through visualization. It enables the user to visualize and create interactive and sharable dashboards. While anyone with some knowledge of MS Excel can learn it, it is in no way an MS Excel clone. It has the power to help solve the most complex analytical problems.

20.Distinguish between .twb and .twbx extension

Answer:

  • twb: This is an xml document in which all the selections and layout created in the Tableau workbook is located. It does not contain any data.
  • twbx: The. twbx is a zipped archive that contains a. twb and any external files such as extracts and background images.

21.Explain the Tableau Data Engine

Answer: The Tableau Data Engine is an analytical database with which instant query response and predictive performance can be generated. It integrates seamlessly into existing data infrastructure and does more than loading entire data sets into memory.

When one works with a large amount of data, the major part of the time is taken up in importing, creating indexes and sorting data, after which everything speeds up. What makes Tableau Data Engine smart is that it is not really an in-memory technology. Since the data is stored in the disk after it is imported; the RAM hardly gets used.

 HR Round:

Describe your career path

  • Why did you choose a career in data visualization?
  • What do you think makes you a successful data visualizer?
  • What has been your working experience with data visualization and how have you overcome challenges associated with this field?
  • What is your performance as a team person?

Conclusion:

Embarking on a career in data visualization? You have a lot coming up. This is an upcoming and flourishing career option for those who can combine both logical thinking and creativity. This field is set to grow in the years to come. Any wonder then that according to payscale.com, a data visualizer can expect to earn upwards of $108,000 in the US? We hope that you will find this Q and A session useful in cracking any interview for data visualizers. We wish you the best!