DEFINITION Graphs are the visual teaching aids for presenting statistical information and contrasting the trends or changes of certain attributes.
TYPES There are four main types of Graphs namely: Bar Graphs Line Graphs Pie Graphs Pictorial Graphs
BAR GRAPHS A bar graphs consists of the bars arranged eitherhorizontally or vertically from a origin base. Twoperpendicular lines from a point (called origin) workas the reference line. Bar are especially useful incomparing and contrasting two variables or two groupson the same attributes.
Some useful points to be keep in mind while preparing a bar chart are as follows:- before making a bar chart make a rough sketch of it in a note book. For drawing the bar graph use the chart paper of 50 x72 cm size. Use different colour shades for the two contrasting groups.
The bar should be equi-spaced. Write the tittle of the chart in bold letters. Write the key to the bar graph in a box on the right hand side corner of the chart paper. Write the numbers on the top and bottom of the each bar.
LINE GRAPHS A free hand smooth line through various points indicating the instantaneous values of two variables at various moments is called line graph. The line may be straight line or curved line indicating the relation ship between two variables.if there are abrupt changes between the variables ,those are shown by dotted lines.
The squares on the graph board or graph paper helps in accurate plotting . Sketch pens or markers can be used to write the caption ,shows x-axis ,y-axis, scale along x-axis ,scale along y-axis and actual curve joining different points.
PIE GRAPHS This graph is usually shown as a disc or circledivided into sectors of different angles to represent thefractions or percentages of the divisions of adistributive attribute.
Some useful points to be keep in mind while preparing a bar chart are as follows:- Find out the angles from the percentage or fraction. Draw the circle on a chart paper of full size using a big compass carrying a sketch or marker pen.
Divide the circle into appropriate sectors using the protractor. Colour each section and write the corresponding percentage. Caption the pie graph in a bold letter.
PICTORIAL GRAPHS A pictorial graph consist of picture of sametype but the different sizes or it may be made with thepictures of same size but different number to representdifferent magnitudes.