Page 250 - ICSE Math 7

22 Data Handling

Key Concepts

• Collection of Relevant Data • Bar Graphs
• Organization of Data • Construction of Bar Graphs
• Measures of Central Tendency • Multiple Bar Graphs

In today’s world with easy access to data, there is hardly any branch of studies, be it Mathematics,
Economics, Science, Medicine, Psychology, etc. where statistical application does not play an important
role. Scientists, businessmen, researchers, economists, etc. with the help of various statistical tools
decide the future course of action and project estimates for future. Meteorologists use statistics to
forecast weather and predict heavy rains and storms.
In the previous class, you have learnt to collect and tabulate data and put it in the form of bar graphs.
Collection, organization and presentation of data is of great significance as it not only helps in analysis
and interpretation but important inferences can be drawn from it.
In this chapter, we are going to learn how to collect relevant data and present it as frequency distribution.
We will also learn to evaluate 3 representative values—mean, median and mode, review bar graph
and learn more about it.

Collection of Relevant Data

Before collecting the data, we should know for what purpose it is needed. In order to get useful results,
one should know clearly what type of problem is at hand and the exact data required for it.

Suppose we need to know the performance of India in the Commonwealth Games. It can have two
interpretations. One is the performance of our country vis-a-vis other countries. For this, we must
have the medal tallies of all the countries in the Commonwealth Games. If the aim is to study the
relative performance of India over the years in the Commonwealth Games, then we need to study the
data regarding the number of medals (Gold, Silver and Bronze) won by India in the Commonwealth
Games vis-a-vis its own performance in the past. Thus, one can observe the difference in the data
required for the two situations.

Discuss with your friends, what type of data is required in the following situations:
• Performance of your class in Mathematics test.
• Children whose parents are in services are more serious in studies.
• Number of members in different families of your neighbourhood.

Organization of Data
The data regarding cricket test matches can give access to lot of information, but we cannot get
quick answers for our specific queries. Its difficult to say which bowler has taken the maximum or
minimum wickets, who has scored the highest runs, etc. In order to get answers to all these queries,
one has to go through the data collected by the scorer or statistician. For example, let the runs scored
by different batsmen in test series be: 30, 86, 42, 115, 93, 17, 23, 55, 90, 10, 5, 41, 69, 102, 74, 118,
98, 4, 110, 13 and 7.

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