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Graphs Index Graphs, why use them?

ALL ABOUT GRAPHS
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Other Types of Graphical Representation Line graphs or curves represent the most commonly used type of graphical analysis but there are others.
Histograms These consist of a series of columns representing a variation in frequency (the number of times an event occurs) of a variable over a discrete interval or class. The example given shows the frequency of flowers in the flower heads of a sample taken from a population of red clover. It is worth noting that the area beneath the histogram is proportional to the frequency of the items being recorded. This is more easily demonstrated on graph paper where you can count up the squares under the columns of the histogram. The distribution of the number of flowers per flower head in a population of red clover Trifolium repens
Bar Charts These are very like histograms except that the columns are not usually adjacent to one another. This is to emphasise the point that these data are not directly related to one another. They could be placed in any order. The effect of different mineral solutions on the germination of lettuce seeds after two days
Pie Charts These graphs look completely different from any other form of graph so far considered. They are used to represent the proportions of a whole, as you can see in the example give. The proportions are based upon the size of the segment that each component occupies out of the whole disk (3.6° representing 1%).
Area Diagrams Alternatively if the proportions are part of a series they may be expressed in a linear fashion as shown below. The relative proportions of invertebrates caught in pitfall traps along a line transect
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