Cartograms or statistical maps are used to give

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Unformatted text preview: on as a geographical basis. They are used to represent 79 spatial distributions. The quantities on the map can be shown in many ways such as through shades or colours or dots or placing pictogram in each geographical unit. 5.6 Graphs: A graph is a visual form of presentation of statistical data. A graph is more attractive than a table of figure. Even a common man can understand the message of data from the graph. Comparisons can be made between two or more phenomena very easily with the help of a graph. However here we shall discuss only some important types of graphs which are more popular and they are 1.Histogram 2. Frequency Polygon 3.Frequency Curve 4. Ogive 5. Lorenz Curve 5.6.1 Histogram: A histogram is a bar chart or graph showing the frequency of occurrence of each value of the variable being analysed. In histogram, data are plotted as a series of rectangles. Class intervals are shown on the ‘ X-axis’ and the frequencies on the ‘ Y-axis’ . The height of each rectangle represents the frequency of the class interval. Each rectangle is formed with the other so as to give a continuous picture. Such a graph is also called staircase or block diagram. However, we cannot construct a histogram for distribution with open-end classes. It is also quite misleading if the distribution has unequal intervals and suitable adjustments in frequencies are not made. Example 10: Draw a histogram for the following data. Daily Wages Number of Workers 0-50 8 50-100 16 100-150 27 150-200 19 200-250 10 250-300 6 80 Solution: HISTOGRAM Number of Workers 30 25 20 15 10 5 0 50 100 150 200 Daily Wages (in Rs.) 250 Example 11: For the following data, draw a histogram. Number of Marks Students 21-30 6 31-40 15 41-50 22 51-60 31 61-70 17 71-80 9 Solution: For drawing a histogram, the frequency distribution should be continuous. If it is not continuous, then first make it continuous as follows. Number of Marks Students 20.5-30.5 6 30.5-40.5 15 40.5-50.5 22 50.5-60.5 31 60.5-70.5 17 70.5-8...
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This note was uploaded on 01/18/2014 for the course BUS 100 taught by Professor Moshiri during the Winter '08 term at UC Riverside.

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