Day 7 - Team E - Kranthi

We have learnt the below from today’s sessions:

• How to create graphs in Excel (Bubble & Radar graphs)?
• How can we interpret those graphs?

Below were the two topics which have been revised in our day’s sessions:

• Discussed the steps in which the attributes are mapped in the permap tool. And an assignment has been given to link the variables with the impacted attributes using cross tabulations in SPSS and come up with two strategies to overcome the problems.
• Creating critical element of Hierarchical clustering – ‘Proximity matrix’ and this table is used to create bubble and radar graphs.

Creating graphs in SPSS tool:

Navigate to Graphs > Legacy Dialogs > Bar graphs

In the popped up dialog box, Category axis is nothing but an X-axis. For “Group cases” option, use only Category variables. For “Variables” option, use only continuous variables. (Even Continuous discrete variables are not used)

There is also an option to transformation the graph from 2d to 3d.

Excel Charts

Bubble Chart

What are they?

A bubble chart is a type of chart that displays three dimensions of data. Bubble charts can be considered a variation of the scatter plot, in which the data points are replaced with bubbles.

How to create them?

• Variables needed – Four
• Two - Continuous variables (for x and Y axis)
• One - Continuous variables (for ‘Size of the bubble’)
• One - Category variable

Variables holding bubbles are category variables because number of bubbles should be limited.

In SPSS tool, navigate to Analyze > Custom table

Drag category variable in rows and drag all the continuous variables in the columns.

Note: Ensure that the variable which is being dragged into the rows section should be a nominal variable, if it is not that type, change its type and then proceed further.

Major Decision – is which one of the column becomes the ‘size of the bubble’? Generally the column in which the values are more deviated becomes the size of the bubble and it is kept in the last column of the table. Once the table is generated with required data it is transferred into an excel and the bubble chart is created.

Below video shows the creation of bubble charts:

Expanding the graph: Using right click on the chart area, go to format axis and make the reqiored changes in order to increase the visibility of the bubbles if required.

Why they are used?

• Bubble charts can facilitate the understanding of social, economical, medical, and other scientific relationships.
• Bubble charts are often used to present financial data. Different bubble sizes are useful to visually emphasize specific values.

Radar Chart

What are they?

A radar chart is a graphical method of displaying multivariate data in the form of a two-dimensional chart of three or more quantitative variables represented on axes starting from the same point. The relative position and angle of the axes is typically uninformative. The radar chart is also known as web chart, spider chart, star chart, star plot, cobweb chart, irregular polygon, polar chart, or kiviat diagram.

How to create them?

Below video shows the creation of radar charts:

Why they are used?

Radar charts are used to:

• To visually depict the incremental improvements over a period of time
• To measure performance against benchmarks
• As a visual snap shot of progress over several criteria

Dimension is the variable made up of several other variables which have something in common. Dimension is most important tool to understand the Factor analysis.

Also discussed that using Google gadget – Motion chart we can create motion charts.