Analyzing, interpreting, and communicating complex data are easier when data are presented visually. Suitable visualizations help stakeholders to understand the patterns, trends, and insights hidden in data. The Microsoft Power BI Data Analyst PL-300 certification exam, tests your ability to identify and implement the most appropriate visualizations for your data.
1. Understanding your Data
The first step to identifying and implementing the appropriate visualization is understanding the nature of your data. It involves understanding the type of variables in your data.
- Categorical: These are non-numerical and include both nominal (e.g., color, gender, country) and ordinal variables (e.g., ratings, class grades).
- Numerical: These are quantitative and they encompass both interval (e.g., temperature in Celsius, dates) and ratio variables (e.g., height, weight, age).
2. Choosing the Appropriate Visualization
Different data types require different visualizations to represent them effectively.
- Bar or Column Chart: Best for representing categorical data. They present categories of data with rectangular bars with heights or lengths proportional to the values that they represent.
- Pie Chart: Suitable when you need to show a numerical proportion for categories as parts of a whole.
- Line Chart: Ideal for expressing trends over time (time series data).
- Histogram: It is useful when you want to represent the frequency distribution in a continuous data set.
- Scatter Plot: Perfect when you want to show the relationship between two numerical variables.
3. Implementing Visualizations with Power BI
In Power BI, creating visualizations is a simple process.
- Start by loading your data into Power BI Desktop.
- Click on the “Report” icon in the left navigation bar.
- Drag the fields you want to visualize from the Fields pane onto the report canvas or onto the visualization pane.
- Power BI will create a default visualization for you, but you change it by selecting another type of visualization from the Visualizations pane.
For example, to create a Pie chart:
- Click on the pie chart icon on the Visualizations pane.
- Drag the categorical field onto the “Axis” or “Legend” area and
- Drag the numerical field onto the “Values” area.
Like this, you can experiment with different visualizations and choose the one most appropriate for your specific data.
4. Customization for Clarity
After choosing the right visualization, customizing it can enhance its clarity and usability. In Power BI, you can customize aspects like title, legend, colors, axes, labels, filters, etc. You do this in the formatting pane, which appears when you select a visualization.
In conclusion, identifying and implementing appropriate visualizations is a fundamental skill for Power BI Data Analysts. Practice with different data types and visualizations to better understand how to represent data in the most insightful way. Remember, the goal is not just to create beautiful visualizations but to create meaningful ones that enable decision-makers to make data-driven choices.
Practice Test
True or False: A pie chart is good to use when you want to show proportional representation in a dataset.
- True
- False
Answer: True
Explanation: Pie charts are best used when you want to compare a single category of data between individual sub-items.
In Microsoft Power BI, which visualization type is best to show trends over time?
- a. Scatterplot
- b. Bar graph
- c. Line chart
- d. Donut chart
Answer: c. Line chart
Explanation: Line charts are an effective way to present data trends over time. They help in spotting trends, patterns, and fluctuations in data over a time period.
True or False: You can use a waterfall chart to demonstrate how a starting value is affected by various positive and negative changes.
- True
- False
Answer: True
Explanation: Waterfall charts are specifically designed to show how a starting value is affected by a series of positive and negative changes.
Which type of chart is most helpful when comparing the part-to-whole relationship in a single snapshot?
- a. Pie chart
- b. Line chart
- c. Area chart
- d. Clustered Column chart
Answer: a. Pie chart
Explanation: A pie chart gives a visual representation of the part-to-whole relationship in a dataset.
In a situation where you need to display a trend and compare values, what’s the most appropriate chart type should be used in Power BI?
- a. Waterfall chart
- b. Pie chart
- c. Line and clustered column chart
- d. Scatter chart
Answer: c. Line and clustered column chart
Explanation: Line and clustered column chart allows both displaying a trend (through line) and comparing values (through columns) at the same time.
True or False: Bubble chart in Power BI can be used to represent three dimensions of data.
- True
- False
Answer: True
Explanation: Bubble chart indeed represents three dimensions, the X-axis data, the Y-axis data, and the Bubble size data.
Which type of chart is best used to visualise hierarchical data in Microsoft Power BI?
- a. Treemap
- b. Line chart
- c. Donut chart
- d. Column chart
Answer: a. Treemap
Explanation: Treemaps are perfect for hierarchical data view, representing categories and subcategories of data.
What type of visualization in Power BI would be best to illustrate the correlation between two quantitative variables?
- a. Pie chart
- b. Scatterplot
- c. Bar chart
- d. Line chart
Answer: b. Scatterplot
Explanation: Scatterplots are ideal for illustrating the correlation between two quantitative variables.
True or False: In Power BI, you cannot use custom visuals downloaded from other sources.
- True
- False
Answer: False
Explanation: Power BI provides the facility to import visuals that have been created by others and shared on the Power BI Visuals marketplace.
Which chart type is appropriate when you want to perform a comparative analysis in Power BI?
- a. Pie chart
- b. Clustered column chart
- c. Line graph
- d. Waterfall chart
Answer: b. Clustered column chart
Explanation: Clustered column charts are used to display, compare, and contrast unique values between individual categories.
True or False: Map visuals in Power BI cannot display geographical data.
- True
- False
Answer: False
Explanation: Power BI has several types of map visuals that can display geographical data, including the standard Map, Filled Map, and Shape Map.
In which chart type are data points shown as symbols?
- a. Scatterplot
- b. Donut chart
- c. Bar chart
- d. Line chart
Answer: a. Scatterplot
Explanation: In a scatterplot, data points are represented as individual markers or symbols.
True or False: A treemap is a visualization for time series data.
- True
- False
Answer: False
Explanation: A treemap is not generally used for time series data. It is used to display hierarchical (tree-structured) data as a set of nested rectangles.
Which foundational chart type can be expressed as a percentage?
- a. Pie chart
- b. Column chart
- c. Line chart
- d. Map chart
Answer: a. Pie chart
Explanation: Pie chart represents the data in a percentage format, ideal for part-to-whole comparison.
True or False: Data bars in Power BI allow you to display the value of an item relative to other items.
- True
- False
Answer: True
Explanation: Data bars are miniature within-cell bar charts. They can be used in a table or matrix to show item value relative to other items.
Interview Questions
What are the four types of visualizations available in Power BI?
The four types of visualizations available in Power BI are Tables and Matrices, Charts, Maps, and Other.
How can you make a pie chart in Power BI?
To make a pie chart in Power BI, first drag the ‘Pie chart’ icon to the report canvas. Then, you can add data to the ‘Values’ area and dimension to the ‘Legend’ area.
What is the purpose of a Power BI slicer visualization?
A Power BI slicer is a type of visualization that filters the data shown in other visualizations. You can adjust your slicers to show specific date ranges, categories, and other segmented views of your data.
Which type of Power BI visualization should you use when you want to display a trend over time?
When you want to display a trend over time, a line chart is an appropriate visualization to use in Power BI.
How can you add a title to a chart in Power BI?
To add a title to a chart in Power BI, you can select the chart, go to the Visualizations pane, then select the Format option and expand the title section. You can then enable the title and enter your desired chart title.
What can be done with the “Other” type of visualizations in Power BI?
The “Other” type of visualizations in Power BI can be used to create unique displays such as cards, gauges, KPIs, and waterfall charts.
How can you create a map visualization in Power BI?
To create a map visualization in Power BI, drag the ‘Map’ icon to the report canvas. Then, add geographic data to the ‘Location’ field well and a measure to the ‘Size’ field well.
Can you create custom visualizations in Power BI?
Yes, Power BI allows you to create your custom visualizations using Power BI Desktop, which can be done using R script visual or Python scrypt visual, or you can import visuals created by others.
In what circumstances might you use a scatter plot in Power BI?
A scatter plot in Power BI is useful when you want to understand the relationship between two numerical variables, especially when looking for trends or clusters.
What is the purpose of using ‘Drillthrough’ in Power BI?
Using ‘Drillthrough’ in Power BI allows users to create a page in their report which focuses on a specific entity such as a supplier, customer, or manufacturer. This makes it easy to filter for specific results with just one click.
How do you customize the colors in a Power BI visualization?
To customize colors in a Power BI visualization, select the visualization, go to the Format pane, and under the Data colors option, choose your desired colors.
Can you apply conditional formatting to a chart in Power BI?
Yes, you can apply conditional formatting to charts in Power BI. This allows you to change the color of the bars, columns, or other aspects of your charts based on the values they represent.
How do you implement hierarchy in Power BI visualizations?
To implement hierarchy in Power BI visualizations, you would first need to create the hierarchy in the Fields pane. You can then use this hierarchy in your visuals by adding it to the Axis or Legend field well.
What is the use of a Power BI KPI visual?
A KPI (Key Performance Indicator) visual in Power BI provides a clearly visible way of tracking progress towards a target. It includes a trend line or graph and displays performance over a time period.
How do you save a customized visual as a template in Power BI?
In Power BI, you cannot directly save a customized visual as a template. However, you can save the entire report as a template, and use it for future reports.
extutorials.com