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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 ‘ Xaxis’ and the frequencies on the
‘ Yaxis’ .
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 openend 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
050
8
50100
16
100150
27
150200
19
200250
10
250300
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
2130
6
3140
15
4150
22
5160
31
6170
17
7180
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
20.530.5
6
30.540.5
15
40.550.5
22
50.560.5
31
60.570.5
17
70.58...
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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.
 Winter '08
 Moshiri
 Business

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