Discrete: only definite values
Continuous: all values within range
Frequency Polygon: to compare the trend of 2 histograms
How to draw? Split the top of each bar of the graph in half, connect the middle points of the top of the bars together.
Figure 1.1 - Frequency Polygon (source: Wikibooks)
Rearranging of data in ascending order which makes it easier to find median term.
Things important in graphs