Visualization techniques for continuous variable data

Continuous variables have a different structure and, hence, we need specialized methods for displaying them. Fortunately, many popular graphical techniques are suited very well for continuous variables. As the continuous variables can arise from different phenomena, we consider many techniques in this section. The graphical methods discussed in this section may also be considered as a part of the next chapter on exploratory analysis.

Boxplot

The boxplot is based on five points: minimum, lower quartile, median, upper quartile, and maximum. The median forms the thick line near the middle of the box, and the lower and upper quartiles complete the box. The lower and upper quartiles along with the median, which is the second quartile, divide the data into four regions, with each containing equal number of observations. The median is the middle-most value among the data sorted in the increasing (decreasing) order of magnitude. On similar lines...