11.3.1 Graphic presentation of scientific data: Need and its importance
Biostatistical values (data) are documented in the form figures and are usually recorded in the form of tables. But numerical or arithmetical figures are usually not attractive. Large number of figures in tables are not easily understandable. It seems difficult to get a clear picture from the numerical data. Diagrams and graphs are comparatively more attractive way of presenting the clear and complete picture of data. Moreover, data information presented in the form of diagrams, pictures, charts and graphs leave long lasting impression on the mind of the observer. Multiple types of graphs, pictures and diagrams are used in representing data including bar- chart, rectangles and pie- chart.
11.3.2 Simple bar diagram or simple bar chart
Simple bar chart have bars which are drawn to represent a single data without further classification of the characteristics. Bar chart represent only one characteristic of the data. One bar represents only one value or figure and there may be multiple bars representing many values or figures. In a simple bar chart, bars of equal width are drawn, but their lengths are variable. Heights of length of the bars represent the magnitude of a quantity or degree of value in the data.