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Specially made for commerce students.


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INTRODUCTION When a set of statistical data are presented on a graph paper, it is called a graph. Presenting the data on a graph paper, we gewt different points , each point corresponding to a value of a statistical series. By joining the points we get a line which shows how a variable tends to change. Each point on the line corresponds to an arithmetic value of the variable under study. Therefore, a graph showing arithmetic values of a variable (on a graph paper) is called ‘arithmetic line-graph’. Often such graphs are constructed to present time series data, that is , the data corresponding to different weeks, months or the years. Therefore, arithmetic line graphs are often called ‘time-series graphs’


CONSTRUCTION OF GRAPH A graph includes :- Point of origin (O) Axis : abcissa (x axis) ordinate (y axis) Four quadrants


Intersecting point on the graph paper is assumed as a point of origin as point ‘O’. Horizontal and vertical lines intersecting through point of origin are called axis . Horizontal line from left to right is called horizontal axis, abcissa or X-axis . The line going upward or downward is called vertical axis, ordinate or y-axis . These axis divide the plain of the paper in four parts. Each part is called ‘quadrant’.


2 y 1 - x,+y + x,+y x x 3 4 -x,-y +x,-y y


RULES FOR CONSTRUCTING A GARPH HEADING: Every graph must have a suitable , precise and self explanatory heading. CHOICE OF SCALE: One should fix an appropriate scale on which data should be presented. An appropriate scale is the one by which the entire data are easily represented by the graph.


PROPORTION OF AXIS: As far as possible , length of X-axis on the graph paper should be one and a half times the length of Y-axis. METHOD OF PLOTTING THE POINTS: Economics and business statistics are generally positive. These are to be presented in the first quadrant. Accordingly, the point of origin is to be fixed to the left and lower portion of the graph paper. On the X-axis, the points are plotted from left to right and on the Y-axis, the points are plotted upward from bottom to top.


LINES OF DIFFERENT TYPES: If more than one line or curve line are to be drawn in the same graph, these lines should be differentiated from each other in the form of broken lines (------),dotted lines (……) , bold lines ( _____ ), etc. TABLE OF DATA: It would be useful to give the table of data along with the graph of the data. This helps verification of the graph.


USE OF FALSE LINES: If the values in a series are very large and the difference between the smallest value and zero is high and if these values are to be indicated on Y-axis of the graph, then the Y-axis is started somewhere above the point ‘O ’. TO DRAW A LINE OR CURVE: We mark different points on the graph paper corresponding to different values of a series. These points are joined to make a line or a curve. The joining line must be uniform throughout its length. It should not be of different thickness at its different points.


ONE VARIABLE GRAPH One variable graph are those graphs in which of only one variable are shown with respect to some time period. Graphic presentation of the production of a factory between the months of January or June of a year, would be a one variable graph.


TWO OR MORE THAN TWO VARIABLE These are the graphs in which values of two (or more than two) variables are simultaneously shown with respect to some period of time. Data on the production and sale of a factory in different months would make a two variable graph.

General rules for constructing diagrams and graphs:

General rules for constructing diagrams and graphs PROPER SIZE: Diagrams or graphs must suit the size of the paper. It should be neither too big nor too small. PROPER HEADING: Diagrams or graphs must bear proper heading. A heading must be simple , short and informative.


3. PROPER SCALE: Before making a diagram/graph its scale should be properly determined and indicated . 4. USE OF SIGNS AND COLOURS ONLY: Diagrams or graphs must carry some signs on the nature and classification of information. Colours may be used to indicate different aspects of a diagram. These signs and colours must be clarified.


5. LESS USE OF WORDS OR FIGURES: In diagrammatic or graphic presentation of data one should make minimum possible use of the words and figures . 6. DRAWING THE BORDER: Diagrams or graphs must be bordered with bold lines to make them attractive . 7.SIMPLE: Simplicity is the principal feature of diagrams and graphs. These should not look to be complex and offending.


8. FROM LEFT TO RIGHT OR BOTTOM TO TOP: The construction of diagrams/graphs should flow from left to right or from bottom to top . 9. STATEMENT OF DATA: Data which constitute the basis of diagrams/graphs should be clearly stated . 10. ATTRACTIVE AND EFFECTIVE: Diagrams and graphs must be attractive and effective in communicating the required information.


MERITS OF DIAGRAMMATIC AND GRAPHIC PRESENTATION SIMPLE AND UNDERSTANDABLE INFORMATION: Even the most complex statistical information is made simple and understandable with the help of diagrams and graphs. LASTING IMPACT: Diagrammatic or graphic presentation leaves a lasting impact on the reader’s mind. Information is not easily forgotten. NO NEED OF TRAINING OR SPECIALISED KNOWLEDGE: One needs no training or specialized knowledge reading diagrams and graphs. These are easily understood even by a layman.

ATTRACTIVE AND EFFECTIVE MEANS OF PRESENTATION: Diagrams and graphs are very effective means of presenting data. It is rightly said that a picture is worth of a thousand words. :

ATTRACTIVE AND EFFECTIVE MEANS OF PRESENTATION: Diagrams and graphs are very effective means of presenting data. It is rightly said that a picture is worth of a thousand words. A QUICK COMPARATIVE GLANCE: Diagrams/ graphs facilitate a comparative glance at the data. Thus, data on investment in public and private sectors , when presented in the form of bar diagrams, can be easily compared. One can easily note the broad differences between the two.


INFORMATIVE AND ENTERTAINING: Besides being informative, diagrammatic or graphic presentation is an entertaining means of data presentation. LOCATION OF AVERAGES: Using graphic technique, we can easily locate the values of certain averages, such as mode and median. STUDY OF CORRELATION: Graphic presentation of data corresponding to different variables helps identify correlation between the variables.


LIMITATIONS OF DIAGRAMMATIC AND GRAPHIC PRESENTATION LIMITED USE: Only a limited set of data can be presented in the form of a diagram. In fact, diagrams and graphs are generally use only when comparisons are involved or when time-series data are to be presented. MISUSE: Diagrams may be misused for false4 projection of the statistical facts, especially in case of advertisements. ONLY PRELIMINARY CONCLUSIONS: It may not be always easy to arrive at final conclusions after seeing the diagrams. Multiple information in the form of diagrams and graphs may offer only preliminary conclusions.

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