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Presentation of Data – Class 11 Economics notes, important questions and MCQs

NCERT Class 11 Economics, chapter 4. Notes, key terms, important questions with answers and MCQs.

Chapter overview

Organised data must be presented in a form that is easy to understand and compare. Data can be presented in text, in tables, or in diagrams and graphs. A good table has a number, title, headings, body, unit, source and notes. Diagrams such as bar diagrams and pie charts, and graphs such as histograms, frequency polygons, ogives and line graphs, show patterns at a glance.

Textual and tabular presentation

Textual presentation describes data in sentences; it suits small amounts of data.
A table arranges data in rows and columns for easy comparison.
Parts of a table: table number, title, captions (column headings), stubs (row headings), body, unit of measurement, source and footnotes.

Diagrams

Simple, multiple and component (sub-divided) bar diagrams compare values across categories or time.
A pie diagram shows parts of a whole; the angle of each sector = (value ÷ total) × 360°.
Diagrams attract attention and are easy to remember but show only approximate values.

Graphs of frequency distributions

A histogram shows a continuous frequency distribution with adjacent rectangles whose areas represent frequencies.
A frequency polygon is made by joining the mid-points of the tops of histogram rectangles.
An ogive (cumulative frequency curve) may be 'less than' or 'more than'; the two ogives intersect at the median.
An arithmetic line graph (time series graph) shows how a variable changes over time.

Key terms

Table: an orderly arrangement of data in rows and columns
Stub: the heading of a row in a table
Pie diagram: a circle divided into sectors showing parts of a whole
Histogram: a graph of adjacent rectangles representing a continuous frequency distribution
Ogive: a cumulative frequency curve

Important questions with answers

What are the main parts of a table?2 marks

The main parts of a table are the table number, title, captions or column headings, stubs or row headings, body containing the data, unit of measurement, source of data and footnotes for explanation.

Distinguish between a bar diagram and a histogram.3 marks

A bar diagram shows discrete or categorical data with bars of equal width separated by equal gaps, and only the height of the bars matters. A histogram shows a continuous frequency distribution with adjacent rectangles without gaps, and the area of each rectangle represents the frequency. Bars can be drawn vertically or horizontally, while histograms are drawn vertically.

Explain the different ways of presenting data with examples, and give the merits of diagrammatic presentation.5 marks

Data can be presented in three ways. Textual presentation describes data in words, for example 'In 2011 India's literacy rate was about 74 per cent'; it is suitable only for small data. Tabular presentation arranges data in rows and columns; a good table has a table number, title, captions, stubs, body, unit, source and footnotes, and it allows easy comparison. Diagrammatic presentation uses diagrams and graphs. Bar diagrams, which may be simple, multiple or component, compare values across categories or years. A pie diagram shows the share of components in a total, the angle of each sector being (value ÷ total) × 360°. For frequency distributions, a histogram uses adjacent rectangles, a frequency polygon joins the mid-points of their tops, and ogives show cumulative frequencies, with the 'less than' and 'more than' ogives meeting at the median. An arithmetic line graph shows a time series such as GDP over years. Diagrams are attractive, easy to understand and remember, help comparison and show trends and patterns at a glance, saving time for the reader. However, they show only approximate values and can be misleading if scales are chosen wrongly.

Quick revision

Textual, tabular, diagrammatic.
Table parts: number, title, captions, stubs, body, source.
Pie angle = value ÷ total × 360°.
Ogives intersect at the median.

Exam tips

Practise calculating pie diagram angles: value ÷ total × 360°.
Remember: histograms have no gaps between bars; bar diagrams have equal gaps.

Practice MCQs

Data arranged in rows and columns are called a
1. diagram
2. table
3. graph
4. paragraph
Show answer
Answer: (b) table. Tables help comparison.
The heading of a row in a table is called a
1. stub
2. caption
3. body
4. footnote
Show answer
Answer: (a) stub. Column headings are captions.
A circle divided into sectors to show parts of a whole is a
1. bar diagram
2. pie diagram
3. histogram
4. ogive
Show answer
Answer: (b) pie diagram. Each sector shows a share.
If a state's share is 25 per cent of the total, its angle in a pie diagram is
1. 25°
2. 90°
3. 180°
4. 360°
Show answer
Answer: (b) 90°. 25/100 × 360 = 90.
A graph with adjacent rectangles for a continuous frequency distribution is a
1. bar diagram
2. histogram
3. pie diagram
4. line graph
Show answer
Answer: (b) histogram. There are no gaps between rectangles.
A cumulative frequency curve is called
1. ogive
2. polygon
3. histogram
4. pictogram
Show answer
Answer: (a) ogive. It may be 'less than' or 'more than'.
The 'less than' and 'more than' ogives intersect at the
1. median
2. mean
3. mode
4. range
Show answer
Answer: (a) median. Half the observations lie on each side.
Which diagram is best to show the change in India's GDP over 20 years
1. pie diagram
2. pictogram only
3. histogram
4. arithmetic line graph
Show answer
Answer: (d) arithmetic line graph. It shows a time series clearly.

All chapters of Class 11 Economics

Written by Kundali IQ from standard, well-established facts to help with revision. This is not an official NCERT publication; always read your textbook too.