Economics 3 Marks Question

Distribution of population on the basis of age, sex and literacy in the year 2015 is tabulated below:

The main features of a good statistical table are:

1. It should be clear and brief.
2. It should suit the purpose.
3. It should be represented in a systematic manner.
4. It should be easily understood.
5. It should be self-explanatory.
6. It should avoid abbreviations.

Sometimes we have such a series in which all values except one are approximate to each other. One value is exceptionally high. In order to provide proper shape, the larger bar is broken at the top and the value of each bar is written on the top. Its purpose is to:

1. Save time.
2. Save space.
3. To give a proper shape to the diagram.

As per the question, year 2006 to 2011 and their respective profits are given. Before plotting the graph, a false base line should be prepared in order to make profit scale equal.
A time series graph of given annual profit figures is shown below:

While constructing a histogram which is based on a continuous frequency distribution with equal class-intervals, the following steps should be followed:
Step 1: On the X-axis, the class intervals are specified. The magnitude of class intervals will determine the width of the rectangle.
Step 2: On the Y-axis, the frequencies are plotted, which determine the height of the rectangle.
Histogram presents a frequency distribution arranged in the form of adjacent rectangles, while frequency polygon is a graphical representation of a line joining the mid-values of the top of the frequency rectangles of histogram.

Percentage Bar Diagram.

In one-dimensional diagrams or charts, only the length of the bar is taken into consideration. But in two dimensional diagrams, both its height and width are taken into account for presenting the data. These diagrams, also known as surface diagrams or area diagrams.

Usually, when we draw any graph, the scale on which the graph is measured starts from zero on the y-axis. However, under the situations when the data to be plotted on graph starts from a value which is far above zero, results in the problem of shortage of space on graph. To overcome this problem of shortage of space, a false base line is plotted. False base line is a line which is drawn to grasp the attention of the reader on the fluctuations which usually remains unnoticed.

S. No.	Sub divided Bar Diagram	Multiple Bar Diagram
1.	In Sub divided bar diagram, different components are shown in single bar with divisions.	In multiple bar diagram, different components are shown in different bars.
2.	In Sub divided bar diagrams, 4-5 variables can be shown.	In multiple bar diagram not more than three items can be shown comfortably.
3.	It cannot be used to compare relative importance of different components.	It can be used to compare relative importance of different components.

1. Components of cost in a factory can be effectively presented with the help of 'Component Bar Diagram'.
2. Composition of population of Mumbai by religion can be effectively presented with the help of 'Percentage Bar Diagram'.
3. Agriculture output of six states can be effectively presented with the help of 'Simple Bar Diagram'.

Graphic Presentation gives a visual effect. It is widely used in researches and analysis of data. It is accurate and precise method of presenting data. It works not only as a tool of presenting data but also as a tool of analysis of data. There can be many types of graphs.

The different attributes according to which data in a table can be classified are:

1. Qualitative classification.
2. Quantitative classification.
3. Temporal classification.
4. Spatial classification.

Composition of the population of Delhi by religion: Composition of the population of Delhi by religion can be diagrammatically presented in a simple bar diagram. This diagram is based on a single set of data of numerical data. Here, the X-axis represents different religion and the Y-axis represents the composition of the population of Delhi. According to the composition of the population of Delhi of different religions, the corresponding bars are made of the respective heights to construct a simple bar diagram. This helps compare and analyse the composition of the population of Delhi by religion.

1. To Simplify Complex Data: The basic objective of tabulation is to simplify complex data by presenting it in rows and columns so that it is easily understood.
2. To Compute Statistical Averages: Various statistical averages such as mean, median, mode, etc can be easily computed with the help of tabulated data.

The three advantages of diagrammatic presentation are:

1. Diagrams are attractive and impressive and leave a lasting impression on the mind.
2. They can be used for making quick comparisons.
3. Some frequency diagrams help in determining median, quartiles and mode.
4. They are used in exhibitions, fairs etc. to give information to the common man.
5. They are easy to understand.

Tea Drinking Habits in Mumbai
Habits	Male	Female	Total
Tea Drinkers	62	18	80
Non-Tea Drinkers	8	12	20
Total	70	30	100

The disadvantages of diagrammatic presentation of data are:

1. Through diagrams, the approximate value of the data is presented. Due of this, diagrams indicate only the aggregate behaviour of the variable under study.
2. Diagrammatic presentation of data gives a general view of the variables under study. As such, it is suitable only for preliminary discussions and not for taking the final decision.
3. It can be used to mislead its users. It is generally used by advertisers to mislead the consumers.

The advantages of textual presentation are:

1. This method helps the investigator to express his views on the data.
2. This method is a combination of figures and facts, which makes it easy to understand.

The disadvantages of textual presentation are:

1. This method of presentation is ineffective when the quantity of data is too large.
2. The user of the data has to go through the complete text for understanding the problem under investigation.

Hisrrogram

Tabulation is the process of condensing classified data in the form of a table so that it may be more easily understood, and so that any comparison involved may be more readily made. -D. Gregory and H. Ward
It is a medium of communication of great economy and effectiveness for which ordinary prose is inadequate. In addition to its formation in simple presentation, the statistical table is also a useful tool of analysis. -D. W. Paden and E. F. Lindquist
In classification, data are separated and grouped based on a property of the data common to all values.

1. In tabulation, data is arranged into columns and rows based on characteristics/ properties, or indicators.
2. Tabulation often emphasize on the presentation aspects of the data, while classification is used as a means of sorting of data for further analysis.

A good diagrammatic presentation should have the following features:

1. The presentation should be attractive, accurate, simple and easy to understand.
2. It should communicate the required information effectively.
3. The diagrams drawn to present the data should be proportionate in height and width.
4. As far as possible, the diagrammatic presentation should be self-explanatory. Words and calculation should be avoided in a diagrammatic presentation.
5. In diagrammatic presentation, vertical diagrams should be preferred over horizontal presentation.
6. The data on the basis of which the diagrams are drawn, should be clearly mentioned.

The difference between Histogram and Bar Diagram is given below:

S. No.	Histogram	Bar Graph
1.	It consists of rectangles touching each other.	It consists of rectangles normally separated from each other with equal space.
2.	The frequency is represented by the area of each rectangle.	The frequency is represented by height. The width has no significance.
3.	It is two dimensional where both the width (base) and the length (height of the rectangle) are important.	It is one dimensional in which only length(height) matters while width is arbitrary.

Deviation bar charts are suitable for presentation of net quantities in excess or deficit such as profit, loss, import, or exports. The excess (or positive) values and deficit (or negative) values are shown above and below the base line. These are also called Bilateral Bar Diagrams.Three examples where these can be used:

1. To show profit or loss of a company.
2. To show balance of trade of a country.
3. To show balance of inflow and outflow of cash in a company.

Diagrams lack accuracy as they show only approximate values. Small difference in values are not comprehendible in a diagram. Yet, they are more effective than table in presenting the data because of the below mentioned reasons:

1. They are simple, attractive and capable of creating an impression.
2. They facilitate easy comparison.

Different types of two dimensional diagrams have been explained below:
Rectangles: Since area of a rectangle is equal to the product of its length and width, while making such type of diagrams both length and width are considered. Rectangles are suitable for use in cases where two or more quantities are to be compared and each quantity is sub-divided into several components.
Squares: To construct a square diagram, first the square-root of the values of various figures to be represented is taken and then these values are divided either by the lowest figure or by some other common figure to obtain proportions of the sides of the squares. The squares constructed on these proportionate lengths must have either the base or the center on a straight line. The scale is attached with the diagram to show the variable value represented by one square unit area of the squares.
Circles: Circles are alternatives to squares to represent data graphically. The circles are also drawn such that their areas are in proportion to the figures represented by them. The circles are constructed in such a way that their centers lie on the same horizontal line and the distance between the circles is equal. Since the area of a circle is directly proportional to the square of its radius, the radii of the circles are obtained in proportion to the square root of the figures under representation. Thus, the lengths that were used as the sides of the square can also be used as the radii of circles.

Components of cost in a factory: The components of cost in a factory can be diagrammatically presented in a pie diagram. Values of each component of costs in a factory are first expressed as percentage of the total value of all the components of cost. Different parts of a circle represent the value of different components of cost in a factory.

Following are the merits of a statistical table:

1. Simple Presentation: Statistical table helps in simple presentation of data. Data is easily understood if table is systematically prepared.
2. Helps in Comparison: Statistical table facilitates comparison of data by presenting the data properly in rows and columns.
3. Special Emphasis: Statistical table highlights important characteristics of data. Accordingly, it becomes easy to draw inferences from it.

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The following factors should be kept in mind while preparing a table:

1. Headings should generally be written in the singular form. For example, in the columns indicating goods, the word 'good' should be used.
2. Use of abbreviations should be avoided in the heading or sub-headings of the table.
3. Footnote should be given, only if needed.
4. Size of table should be in accordance with the size of the paper.

The differences between bar diagram and histogram are:

S. No.	Bar Diagram	Histogram
1.	The spacing and the width or the area of bars are all arbitrary. It is the height and not the width or the area of the bar that really matters.	The width in a histogram is as important as its height, which should remain same for all the rectangles.
2.	Bar diagram can be drawn both for discrete and continuous variables.	Histogram is drawn only for a continuous variable.
3.	In bar diagram, some space must be left between consecutive bars.	In histogram, no space is left between two rectangles.

Component Bar Diagram.

Arithmetic line graph is a graph of time series data. In it, time period is shown on the x-axis and the corresponding values of the variable are shown on the y-axis. Arithmetic line graph, also called time series graph is of two types:

1. Graphs of one variable: If only one variable is to be shown then time is measured along the x-axis and the value of the variable on the y-axis.
2. Graphs of two or more variables: When two or more variables are shown on the same graph then different types of lines (dotted lines, broken lines etc.) are preferred to be used.

Difference between one variable graph and two or more than two variable graph are:

S. No.	Basis	One Variable Graph	Two or More than two Variable Graphs
1.	Meaning	One variable graphs are those graphs in which values of only one variable are shown with respect to time period of equal duration	Two or more than two variable graph simultaneously show the value of two or more than two variables with respect to some period of time.
2.	Example	Year 2015 2016 Year 2015 2016 Profit (in '000) 55 70 Sales (in '000) 120 175       Profit (in '000) 55 70

Monthly rainfall in a year: The monthly rainfall in a year can be diagrammatically presented in a bar diagram. In this diagram, data can be presented in the form of bars or rectangles. These bars can be compared by their relative height, and so, the highest monthly rainfall in a year is comprehended easily.

S. No.	Sub divided Bar Diagram	Percentage Bar Diagram
1.	In Sub divided bar diagram, components are shown in absolute quantities.	In percentage bar diagram, quantities are shown in percentages.
2.	In Sub divided bar diagrams, all bars are of different size.	In percentage bar diagram, all bars are of equal height.
3.	It cannot be used to compare relative importance of different components.	It can be used to compare relative importance of different components.

Format of a table
Table Number Title

Stub heading	Caption
	Column heading	Column heading
Stub entries	Body

Foot note
Source note

When information is presented over a period of time, it is called time series graph. In it, time (hour, day/ date, week, month, year, etc.) is plotted along x-axis and the value of the variable (time series data) along y-axis. A line graph by joining these plotted points, thus, obtained is called arithmetic line kograph (time series graph). It helps in understanding the trend, periodicity, etc. in a long term time series data. An example is given below.

The disadvantages of diagrammatic presentation of data are:

1. Through diagrams, the approximate value of the data is presented. Due of this, diagrams indicate only the aggregate behaviour of the variable under study.
2. Diagrammatic presentation of data gives a general view of the variables under study. As such, it is suitable only for preliminary discussions and not for taking the final decision.
3. It can be used to mislead its users. It is generally used by advertisers to mislead the consumers.