Bar diagrams are one of easiest and the most commonly used devices of presenting most of the business and economic data. These are satisfactory for categorical data or series. They consist a group of equidistant rectangles, one of each group or category of the data in which the values or the magnitudes are represented by the length or height of the rectangles, the width of the rectangles being arbitrary and immaterial. These diagrams are called one-dimensional because in such diagrams only one dimension viz., height (or length) of the rectangles is taken into account to present the given values. The following points may be borne in mind to draw bar diagrams. i. All the bars drawn in a single study should be uniform (through arbitrary) width depending on the number of bars to be drawn and the space available. ii. Proper but uniform spacing should be given between different bars to make the diagram look more attractive and elegant. iii. The height (length) of the rectangles or bars are taken proportional to magnitude of the observations, the scale being selected keeping in view the magnitude of the largest observation. iv. All the bars should be constructed on the same base line. v. It is desirable to write the figures (magnitudes) represented by the bars at the top of the bars to enable the reader to have a precise idea of the value without looking at the scale. vi. Bars may be drawn vertically or horizontally. However, in practise, vertical bars are generally used because they give an attractive and appealing get up. vii. Wherever possible the bars should be arranged from left to right (from top to bottom in case of horizontal bars) in order of magnitude to give a pleasing effect.
Types of Bar Diagrams. The following are the various types of bar diagrams in common use: a) Simple bar diagram.
b) Sub-divided or component bar diagram.
c) Percentage bar diagram.
d) Multiple bar diagram.
e) Deviation or...