A graph refers to the plotting of different valves of the variables on a graph paper which gives the movement or a change in the variable over a period of time. Diagrams can present the data in an attractive style but still there is a method more reliable than this. Diagrams are often used for publicity purposes but are not of much use in statistical analysis. Hence graphic presentation is more effective and result oriented.
Diagrams can present the data in an attractive style but still there is a method more reliable than this. Diagrams are often used for publicity purposes but are not of much use in statistical analysis. Hence graphic presentation is more effective and meaningful.
According to A. L. Boddington, "The wandering of a line is more powerful in its effect on the mind than a tabulated statement; it shows what is happening and what is likely to take place, just as quickly as the eye is capable of working."
Advantages of Graphs
The presentation of statistics in the form of graphs facilitates many processes in economics. the main uses of graphs are as under:
- Attractive and Effective presentation of Data: The statistics can be presented in attractive and effective way by graphs. A fact that an ordinary man can not understand easily, could understand in a better way by graphs. Therefore, it is said that a picture is worth of a thousand words.
- Simple and Understandable Presentation of Data: Graphs help to present complex data in a simple and understandable way. Therefore, graphs help to remove the complex nature of statistics.
- Useful in Comparison: Graphs also help to compare the statistics. IF investment made in two different ventures is presented through graphs, then it becomes easy to understand the difference between the two.
- Useful for Interpretation: Graphs also help to interpret the conclusion. It saves time as well as labour.
- Remembrance for long period: Graphs help to remember the facts for a long time and they cannot be forgotten.
- Helpful in Predictions: Through graphs, tendencies that could occur in near future can be predicted in a better way.
- Universal utility: In modern era, graphs can be used in all spheres such as trade, economics, government departments, advertisement, etc.
- Information as well as Entertainment: Graphs help us in entertainment as well as for providing information. By graphs there occurs no hindrance in the deep analysis of every information.
- Helpful in Transmission of Information: Graphs help in the process of transmission as well as information of facts.
- No Need for training: When facts are presented through graphs there is no need for special training for these interpretations.
Rules for the construction of Graph
The following are the main rules to construct a graph:
- Every graph must have a suitable title which should clearly convey the main idea, the graph intends to portray.
- The graph must suit to the size of the paper.
- The scale of the graph should be in even numbers or in multiples.
- Footnotes should be given at the bottom to illustrate the main points about the graph.
- Graph should be as simple as possible.
- In order to show many items in a graph, index for identification should be given.
- A graph should be neat and clean. It should be appealing to the eyes.
- Every graph should be given with a table to ensure whether the data has been presented accurately or not.
- The test of a good graph depends on the case with which the observer can interpret it. Thus economy in cost and energy should be exercised in drawing the graph.
Following are the main drawbacks/ limitations of graphs.
Limited Application: Graphic representation is useful for a common man but for an expert, its utility is limited.
Lack of Accuracy: Graphs do not measure the magnitude of the data. They only depict the fluctuations in them.
Subjective: Graphs are subjective in character. Their interpretation varies from person to person.
Misleading Conclusions: The person who has no knowledge can draw misleading conclusions from graphs.
Simplicity: Graph should be as simple as possible.
Index: In order to show many items in a graph, index for identification should be given.
How to choose a scale for a graph?
The scale indicates the unit of a variable that a fixed length of axis would represent. Scale may be different for both the axes. It should be taken in such a way so as to accommodate whole of the data on a given graph paper in a lucid and attractive style. Sometimes data to be presented does not have low values but with large terms. We have to use the graph so as it may present the given data for comparison even.
Define various types of graphs.
Types of Graphs
There are two types of graphs.
- Time series Graphs or Historigrams.
- Frequency Distribution Graphs.
Time series graphs may be of one variable, two variables or more variables graph. Frequency distribution graphs present (a) histograms (b) Frequency Polygons (c) Frequency Curves and (d) Ogives.