Ok! , now it’s time for my second blog... Since in today’s class we were not given any assignment, the overall atmosphere was very light at the end of the class J and the reason for no assignment was that we didn’t learn much in today’s class, so I have decided to blog about Radar and Bubble Graphs today.
Radar graphs are used when one wants to look at several different factors related to one item. They have multiple axis along which data can be plotted. Radar chart is also known as web chart, spider chart, star chart, star plot, cobweb chart, irregular polygon, polar chart, or kiviat diagram. Now those are lot of names for one chart!!! Radar charts are used for control of quality improvement to display the performance metrics of any ongoing program. They are widely being used in sports to chart a player’s strengths and weaknesses. For example, you could use a radar chart to compile data about a wide receiver on a professional football team. On one axis, you could plot the percentage of passes caught. Another axis would show his yards per completion; another, his completions per 100 plays; another, blocks made; and a final axis might show his interceptions. If a team did this for all their wide receivers, they could easily spot the best player as well as each player's strengths and weaknesses. Radar charts are helpful for small-to-moderate-sized multivariate data sets. One of the weaknesses is that the effectiveness of radar graphs is limited to data sets with less than a few hundred points. After that, they tend to be overwhelming.
Before I start writing about bubble graphs I think everyone should check out this link: http://www.youtube.com/watch?v=RUwS1uAdUcI. Very interesting representation of data by Mr. Hans Rosling using the bubble graph.
Bubble graphs are a sub type of Plot graphs. A third data value, called the bubble data value, is added to each data item. It is used to determine the size of the bubble. A bubble graph can be used for three dimensional data or time data items. The circles in a bubble chart represent different data values, with the area of a circle corresponding to the value. Bubble chart uses area to represent numbers and hence it is suitable for positive values. If there are negative values they will be shown in different colours. A bubble chart can be used in project management to compare the risks and rewards associated among projects. In a chart each project can be represented by a bubble, the axis can represent the net present value and probability of success and the size of the bubble can represent the overall cost of the project.
Sources: http://en.wikipedia.org/wiki/Bubble_chart, http://www.corda.com/docsource/doc7/Manuals/graph_ref/bubble_graphs.htm http://www.skymark.com/resources/tools/radar_charts.asp, http://en.wikipedia.org/wiki/Radar_chart
Submitted By: Gargi Koyande (13077): Marketing 2.