Representation of Data
2. Tabular presentation:Its principles 2.1. Table should be understandable this achieved by: a. Abbreviations or symbols should be explained in detail at a footnote. b. Row and column should be labeled clearly. c. Title should be clear, concise, and written separated from the body of table by lines or spaces. d. Total should be shown. 2.2. Table should be simple; therefore; simple two or three tables preferred on single large table, data can be summarized in simple method by master table.
3. Graphical presentation:
Graphs used to display a quantitative data using coordinate system where X the horizontal axis ( method of classification), and Y is the vertical axis ( frequency or rate of occurrence). Its principles include: 3.1. Graph should be self explanatory. 3.2. The simplest graphs are the most effective. 3.3. Title may be placed at the top or the bottom of the graph. 3.4. Variables should be labeled clearly by means of key.*Types of graphs: 1. Arithmetic scale line graph. 2. Semilogarithmic scale line graph. 3. Histogram: Its used only for presenting a frequency distribution of quantitative data. There is No space between the cells, scale break should not be used in the histogram. 4. Frequency polygon: Its used to represent more than one set of data. Its constructed from a histogram by a series of straight lines connecting the midpoints of the class interval. 5. Scatter diagram: In a scatter diagram a pair of measurement is plotted as a single point on the graph.
4. Pictorial representation (CHARTS):
It can convey many different types of information including length, proportion….*Types of charts:1. Charts based on length:1.1. Pictogram: Its used a series of small identifying symbols to present data. Each symbols represent a fixed number of items. The figure arranged horizontally or vertically. 1.2.Bar chart: Bars should be had the same width, there are spaces between columns. Its used for discontinuous (discrete) data.2. Charts based on proportion: 2.1. Component bar charts: They are used bars that are shaded or colored. 2.2. Pie charts: Its use a wedge shaped portions of a circle to illustrate a division of the whole into sements. Start at 12 o`clock position and arrange segments in the order of their magnitude (from largest to smallest proportion). To convert from percentage to degrees, multiply the percentage by 3.6 (360/100). 3. Flow charts: The sequence of a series of events is often illustrated by a flow chart. 4. Geographic coordinate charts: Its used by those who show the geographic distribution of disease using maps.