Teaching:TUW - UE InfoVis WS 2008/09 - Gruppe 02 - Aufgabe 1 - Scatterplot
A scatterplot (also called a scatter chart, scatter diagram or scatter graph [Wikipedia]) is a diagram in which the values of two variables are applied to the horizontal and vertical axes of a cartesian coordinate system. The resulting point in the graph represents one record from a data set. The distribution pattern of points from multiple records reveal the correlation between the selected variables in the data set. The scatterplot is not to be confused with the correlation plot [Information Technology Lab, NIST #2] which treats already adopted correlation coefficients of different data groups, while the term correlation diagram does not seem to be bound.
Revealed Information
correlation patterns -> type of correlation (regression line, regression "path", "scatterplot smoothing" [NetMBA]) sign, strength (TODO: add about figures with: perfect positive, strong tight negative, weak loose positive, no correlation, clusters)
density (-> cluster analysis) & outlyers
Scatterplots of higher dimensions
Not necessarily two variables, higher dimensions displayed spacially or by point properties (color, size, shape)
Treating Discrete Data
[Wikipedia, DE]
References
- Wikipedia, EN: http://en.wikipedia.org/wiki/Scatterplot
- Wikipedia, DE: http://de.wikipedia.org/wiki/Streudiagramm
- University of Illinois: http://www.mste.uiuc.edu/courses/ci330ms/youtsey/scatterinfo.html
- Information Technology Lab, NIST #1: http://www.itl.nist.gov/div898/handbook/eda/section3/eda33q.htm
- Information Technology Lab, NIST #2: http://www.itl.nist.gov/div898/handbook/eda/section3/linecorr.htm
- NetMBA: http://www.netmba.com/statistics/plot/scatter/
- ChartItNow: http://www.chartitnow.com/scatter%20diagram.html