Thursday, September 13, 2012

DAY 7 - Team I


Bubble Chart

Bubble chart is a type of chart that displays three dimensions of data. Bubble chart can be considered a variation of the scatter plot in which the data points are replaced with bubbles. A bubble chart is one of the shapes used to represent and interpret data into meaning that is applicable to the user. A bubble chart displays a set of numeric values as circles. It is especially useful for data sets with dozens to hundreds of values, or with values that differ by several orders of magnitude. Bubble charts can be created in a range of standard data applications such as Excel.
Now the Question is when do we use a Bubble Chart ?
One should use a Bubble chart when you want specific values to be represented in your chart by different bubble sizes. Bubble charts are useful when your worksheet has any of the following types of data:

·         Three values per data point: Three values are required for each bubble and they must be in the following order: x value, y value, and then size value.
·         Negative values: Bubble sizes can represent negative values, although negative bubbles do not        display in the chart by default. Even though the size of negative bubbles is based on a positive value, their data labels will show the true negative value.
·         Multiple data series: Plotting multiple data series in a Bubble chart is similar to plotting multiple data series in a Scatter chart. While Scatter charts use a single set of x values and multiple sets of y values, Bubble charts use a single set of x values and multiple sets of both y values and size values.

The example that we took in class was of Cell Inter.

First we  Create a proximity matrix using SPSS as shown below .



Then we copy the Proximity matrix table to excel and then to notepad and make the notepad file PERMAP compatible by writing the syntax above the data table




Once we have done this we will import the fie into PERMAP






Lastly we will insert the bubble chart and have the data ready for analyzing.





Author

Pulkit Kabra

Team I

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