Midpoints of the interval of corresponding rectangle in a histogram are joined collectively by straight traces. It offers a polygon i.e. a determine with many angles.
It’s used when two or extra units of information are to be illustrated on the identical diagram comparable to demise charges in people who smoke and non-smokers, start and demise charges of a inhabitants and so forth.
One option to type a frequency polygon is to attach the midpoints on the high of the bars of a histogram with line segments (or a easy curve). In fact the midpoints themselves may simply be plotted with out the histogram and be joined by line segments. Typically it’s helpful to indicate the histogram and frequency polygon collectively.However generally, the frequency polygon is rather more correct than the histogram as a result of you possibly can consider which is the low level and the excessive level.
Not like histograms, frequency polygons may be superimposed in order to match a number of frequency distributions.
Frequency polygons had been created within the 19th Century as a approach of not solely storing knowledge, however making it simply accessible for people who find themselves illiterate.
- Pearson, Karl. “Contributions to the mathematical idea of evolution. II. Skew variation in homogeneous materials.” Philosophical Transactions of the Royal Society of London 186.Half I (1895): 343-424.