Statistics
 In a pictograph, pictures of objects are used for representing data. Tally marks cannot be used for representing huge numbers. However, these numbers can be represented with the help of pictographs.
 Data can also be represented by using bar diagram or bar graph. In a bar graph, bars of uniform width are drawn horizontally or vertically. These bars are placed at equal distance from each other. The length of each bar gives the required information.
 The data in an unorganised form is called raw data. In order to draw meaningful inferences from a data, we need to organise the data systematically.
We can organise a data in the following ways:

 Frequency distribution table
 Histogram
 Pie chart
 Construction of grouped frequency distribution table:
There are two ways to group the data to make frequency distribution table. These are as follows:
Inclusive method (Discontinuous form):
The classes can be defined in inclusive method as 1  10, 11  20, 21  30 and 31  40. Here, both limits are inclusive in each class.
Exclusive method (Continuous form):
In exclusive method, we take the class intervals as 0 – 10, 10 – 20, 20 – 30. The observ…
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