CBSE Class 8 Math, Introduction to Graphs

Class VIII Math
Notes for Introduction to Graphs
   Pictorial and graphical representation are easier of understand.
   Bar graphs and pie graphs are used for comparing categories and parts respectively.
   A histogram is a bar graph that shows data in intervals.
   A line graph displays data that change continuously over periods of time.
   A line graph being wholly an unbroken line is called a linear graph.
   For fixing a point the graph sheet we take two mutually perpendicular lines called axes.
   The horizontal line of the axes is called the x-axis and the vertical line is called the y-axis.
        The purpose of drawing a graph is to show numerical facts in usual form so that they can be understood quickly, easily and clearly. We also know that a bar graph is used to show a comparison among categories. A bar graph may consists of two or more parallel horizontal or vertical bars of equal width.
        A pie-graph is used to compare various parts of a whole using a circle. A histogram is a bar-graph that shows data in intervals. It has adjacent bars over the intervals as shown below.
        A line-graph is called a linear-graph and it displays data that changes continuously over periods of time.