Diagrammatic Presentation of Data

BASICS OF DIAGRAMMATIC PRESENTATION

(A) CONCEPT OF DIAGRAMMATIC PRESENTATION

  • Diagrammatic presentation is a technique of presenting numeric data through Pictograms, Cartograms, Bar Diagrams & Pie Diagrams etc. It is most attractive and appealing way to represent statistical data. Diagrams help in visual comparison and have a bird’s eye view.
  • Under Pictograms we use pictures to present data. For example, if we have to show the production of cars, we can draw cars. Suppose, production of cars is 40,000. We can show it by a picture having four cars, where 1 Car represents 10,000 units.
  • Under Cartograms we make use of maps to show geographical allocation of certain things.
  • Bar Diagrams are rectangular in shape placed on the same base. Their height represents magnitude/value of the variable. Width of all the bars and gap between the two bars is kept same.
  • Pie Diagram is a Circle which is sub-divided or partitioned to show the proportion of various components of the data.
  • Out of the above only One Dimensional Bar Diagrams and Pie Diagrams are in our scope.

(B) GENERAL GUIDELINES

  • Title – Every diagram must be given a suitable ‘Title’ which should be small and self-explanatory.
  • Size – Size of the diagram should be appropriate neither too small nor too big.
  • Paper used – Diagrams are generally prepared on blank paper.
  • Scale – Under one dimensional diagrams especially ‘Bar Diagrams’ generally Y-axis is more important from the point of view of decision of scale because we represent magnitude along this axis.
  • Index – When two or more variables are presented and different types of line/shading patterns are used to distinguish, then an index must be given to show their details.
  • Selection of Proper Type of Diagram – It’s very important to select the correct type of diagram to represent data effectively.

THEORY QUESTIONS-ANSWERS

Q.1- WHAT IS DIAGRAMMATIC PRESENTATION? DISCUSS THE ADVANTAGES OF DIAGRAMMATIC PRESENTATION.

ANSWER:

(A) DIAGRAMMATIC PRESENTATION

Diagrammatic presentation is a geometric technique of presenting numerical information through Bar Diagrams, Pie Diagram, Pictograms, Cartograms etc. etc.

(B) FOLLOWING ARE THE ADVANTAGES OF DIAGRAMMATIC PRESENTATION:

(1) DIAGRAMS ARE ATTRACTIVE AND IMPRESSIVE:

  • Data presented in the form of diagrams are able to attract the attention of even a common man.

(2) EASY TO REMEMBER

  • Diagrams have a great memorizing effect.
  • The picture created in the mind by diagrams last much longer than those created by figures presented through tabular form.

(3) DIAGRAMS SAVE TIME

  • It presents the complex mass data in a simplified manner.
  • Data presented in the form of diagrams can be understood by the user very quickly.

(4) DIAGRAMS SIMPLIFY DATA

  • Diagrams are used to represent a huge mass of complex data in simplified and intelligible form, which is easy to understand.

(5) DIAGRAMS ARE USEFUL IN MAKING COMPARISONS

  • It becomes easier to compare two sets of data visually by presenting them through diagrams.

(6) MORE INFORMATIVE

  • Diagrams not only depict the characteristics of data, but also bring out other hidden facts and relations which are not possible from the classified and tabulated data.

Q.2- DEFINE ‘ONE DIMENSIONAL DIAGRAM’. BRIEFLY EXPLAIN THE TYPES OF ONE-DIMENSIONAL DIAGRAM.

ANSWER:

(A) ONE DIMENSIONAL DIAGRAM

  • One dimensional diagram is that diagram in which only length of the diagram is considered.
  • It can be drawn in the form of a line or in various types of bars.

(B) FOLLOWING ARE THE TYPES OF ONE-DIMENSIONAL DIAGRAM:

(1) SIMPLE BAR DIAGRAM

Simple Bar diagram comprises of group of rectangular bars of equal width for each class or category of data.

(2) MULTIPLE BAR DIAGRAM

This diagram is used when we have to make comparison between two or more variables like income and expenditure, import and export for different years, marks obtained in different subjects in different classes, etc.

(3) SUB-DIVIDED BAR DIAGRAM

This diagram is constructed by sub-dividing the bars in the ratio of various components.

(4) PERCENTAGE BAR DIAGRAM

Sub-divided bar diagram presented on percentage basis are known as Percentage Bar Diagram.

(5) BROKEN-SCALE BAR DIAGRAM

This diagram is used when the value of one observation is very high as compared to the others.

In order to gain space for the smaller bars of the series, the largest bars may be broken.

The value of each bar is written on the top of the bar.

(6) DEVIATION BAR DIAGRAM

Deviation bars are used for representing net changes in data like Net Profit, Net Loss, Net Exports, Net Imports, etc.

Q.3- WHAT KIND OF DIAGRAMS ARE MORE EFFECTIVE IN REPRESENTING THE FOLLOWING?

(A) MONTHLY RAINFALL IN A YEAR.

(B) COMPOSITION OF THE POPULATION OF DELHI BY RELIGION.

(C) COMPONENTS OF COST IN FACTORY. (NCERT)

ANSWER:

(A) MONTHLY RAINFALL IN A YEAR.

Simple Bar Diagram

(B) COMPOSITION OF THE POPULATION OF DELHI BY RELIGION.

Sub-divided Bar Diagram

(C) COMPONENTS OF COST IN FACTORY.

Pie Diagram or Percentage Bar Diagram.

Q.4- WHAT DO YOU MEAN BY ‘PIE DIAGRAM’? DISCUSS THE STEPS INVOLVED IN CONSTRUCTING IT.

ANSWER:

(A) MEANING OF PIE DIAGRAM

  • A Pie Diagram is a circle divided into sections.
  • The size of the section indicates the magnitude of each components as a part to the whole.

(B) STEPS INVOLVED IN CONSTRUCTING PIE DIAGRAM

  1. Convert the given values in percentage form and multiply it with 3.6’ to get amount of angle for each item.
  2. Draw a circle and start the diagram at 12’O clock position.
  3. Take highest angle first with protector (D) and mark lower angles successively.
  4. Shade different angles differently to show distinction in each item.

Q.1- WHY DIAGRAMMATIC PRESENTATION IS BETTER THAN TABULATION OF DATA?

ANS: It makes data more attractive as compared to tabulation and helps in visual comparison.

Q.2- WHY MEDIA PERSONS PREFER DIAGRAMMATIC PRESENTATION OF DATA?

ANS: Because it has ‘eye-catching effect’ and long lasting impact upon its reader/viewers.

Q.3- WHAT WILL BE THE DEGREE OF AN ANGLE IN THE PIE-DIAGRAM, IF A FAMILY SPENDS 50% OF ITS INCOME ON FOOD?

ANS: (50÷100) X 360 (Or) 50 x 3.6 = 180’

Q.4- WHICH BAR DIAGRAM IS USED TO SHOW TWO OR MORE CHARACTERISTICS OF THE DATA?

ANS: Multiple bar diagram

Q.5-MENTION THE TOTAL OF THE DEGREES OF ALL THE ANGLES FORMED AT THE CENTRE OF A CIRCLE.

ANS: 360°

Q.6-NAME A BAR DIAGRAM WHERE HEIGHT OF ALL THE BARS IS THE SAME.

ANS: Percentage Bar Diagram

Q.7-WHICH DIAGRAM CAN BE USED TO DEPICT VARIOUS COMPONENTS OF A VARIABLE?

ANS: Sub-Divided Bar Diagram

Q.8-WHAT IS A MULTIPLE BAR DIAGRAM?

ANS: Multiple Bar diagram is one that shows more than one characteristic of data.

Q.9-WHICH BAR DIAGRM IS USED TO REPRESENT NET CHANGES IN DATA?

ANS: Deviation Bar diagram.

Q.10-WHAT IS ANOTHER NAME OF SUB-DIVIDED BAR DIAGRAM?

ANS: Component Bar Diagram.