Objective

Every day we come across many numerical data in newspapers, magazines and on television. In this chapter we shall learn the Meaning of Data, Collection, Recording of Data and Organization of a Data.

Data

The word ‘Data’ means collection of information in the form of numerical figures, or a set of given facts. A data is a collection of numbers gathered to give some information. Visual representation of data will help us to understand it better and remember the facts easily.

Example:

• The marks obtained by 10 students of a class in a test are:

 76, 83, 95, 100, 56, 32, 80, 67, 75, 46

• The following table gives the data regarding the favourite game of 100 students of a school:

Recording Data

The data is collected and recorded by the investigator with a definite objective in mind. The data may be collected individually by sending some questionnaires or some other instrument for data collection.

Here, we want to collect data list of the entire student name and their choice of fruit, hence we are recording the choice of fruit of each student. Here each entry is a numerical fact and it is called observation. After tabulating the data and representing it graphically we can reach to some meaningful conclusions.

Organisation of Data

The data that is collected for the first time is called raw data or ungrouped data. When the data is arranged in any data it becomes grouped data. When the data is very large, it is difficult to arrange them in a grouped form. In that case small bars are used to represent data; such method is called Tally Method.

To get the required information, all observations should be recorded. We depict each observation with the help of tally marks.
Tally marks are used to organise the observations. Record every observation by a vertical mark, but every fifth observation should be recorded by a mark across the four earlier marks. The fifth observation tally mark looks like this:

For example, we have a group of persons and their sizes of shoes. The tabular form representing the tally marks is as shown here. Here shows the count to be five plus three (i.e. eight).

Summary

• We have seen that data is a collection of numbers gathered to give some information.
• We have seen how we collect data and each entry is a numerical fact and it is called observation.
• We have seen how to record the data using tally marks.
• Tally marks help us to get particular information from the given data quickly.