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Data Handling

Data is defined as a collection of numbers which give the required information. For example, marks scored by the students in a class, number of members in a family, number of books sold etc.

Data are of two types:

(i) Primary data: It is the data collected by the person directly for a specific purpose without referring any source. Primary data is collected through surveys, local sources etc.

(ii) Secondary data: It is the data collected through other sources like research organizations, financial institutions etc. 

The original form of data is called raw data. But when the data is arranged in ascending or descending order, it is referred to as array

Example: The marks obtained by 10 students in a test out of 30 are as follows:

10, 15, 25, 22, 12, 18, 28, 29, 17, 18

This data is in the form of raw data or ungrouped data. 
Now, after arranging the given data in ascending order we get  10, 12, 15, 17, 18, 18, 22, 25, 28, 29 and on arranging them in descending order we get 29, 28, 25, 22, 18, 18, 17, 15, 12, 10. 
Such arrangement of the data in ascending or descending order is called an array. 

There are different ways of representing the data.

Below given chart explain the same.  

To understand how to represent the given data using tally marks, look at the following video.

In this video we have seen that the use of tally marks has made the data simpler to understand.


Let us now discuss some examples based on representation of a data through tally marks.

Example 1:

A survey was conducted in a village of 80 people. The blood groups of 80 people are as follows.

A, AB, A, B, O, AB, A, AB, O, B, A, O, O, B, A, A, B, AB, O, AB, O, B, A, O, B, O, A, O, A, AB, A, B, AB, O, B, O, O, B, AB, O, A, A, B, AB, AB, O, B, O, O, B,

O, O, B, A, A, O, O, B, O, O, AB, O, B, O, AB, O, A, O, O, B, A, AB, AB, A, B, AB, O, B, O, O.

Represent this data using tally marks.


The given data is rep…

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