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Here the weights (in kg) of 30 students in a class are given below.
48, 47, 60, 45, 47, 55, 47, 55, 60, 68,

47, 47, 55, 60, 42, 55, 47, 55, 68, 42,
55, 60, 35, 42, 47, 55, 47, 55, 35, 55

Answer the following questions:
1. What is called this type of data?

2. Find the number of students who weigh 47 kg.
3. Find the number of students who weigh 55 kg or less
4. Find the number of students who weigh between 40 kg and 50 kg.

5. What weight does maximum number of students have?
6. Make a frequency distribution table for this collection of data.

Data

Data is the collection of information often presented in the form of numbers. There are two types
of data:

Data collected firsthand by a researcher, using methods like surveys, interviews, or experiments
is called primary data.
Data obtained from a source other than the researcher, gathered from published or unpublished
sources is called secondary data.

Raw Data: The data obtained in the original form directly gathered from its source is called raw data.
Suppose the marks (out of 25) obtained by 20 students in an examination are:

17 24 23 17 11 17 23 21 20 21

24 1 17 15 19 20 11 17 17 13
The collection of these marks of 20 students is raw data.

Array data: If we arrange the marks in ascending or descending order, then the data arranged in
a specific order will be called ‘arrayed data’.

Organization of Data

We know that if the collected data are very large, then
it is very tedious and difficult to use it for meaningful Knowledge Desk
conclusions. Suppose we have the marks obtained
by 20 students in a test out of 25 marks. We want to ‘Statistics’ is a branch of mathematics
know the number of students who got marks less that deals with the collection, presentation,
analysis, and interpretation of data. It helps
than 15 or more than 15 or 15, then it is not easy in understanding and drawing conclusions
to extract the answers directly from the data. Even from the given data using various methods to
arranging the data in ascending or descending order summarise and interpret numerical information.
is also a very tedious and time consuming task.

307 Data Handling