Chapter 13 — Introduction to Graphs

Introduction

Graphs are visual representations of data. .Graphical presentation of data is easier to understand. It gives us a clear picture of how quantities change.

The most used graph in this chapter is the line graph:

  • A line graph displays data that changes continuously over periods of time.
  • A line graph which is a whole unbroken line is called a linear graph.
  • For fixing a point on the graph sheet we need its x-coordinate and y-coordinate.
  • The relation between a dependent variable and an independent variable is shown through a graph.
Note: The horizontal axis is called the x-axis and the vertical axis is called the y-axis. The point where they meet is the origin written as (0, 0).
Example 1 — Simple line graph (data over days)
Mon Tue Wed Thu Fri Sat 10°C 15°C 20°C 25°C 30°C
Figure: Line graph showing temperature across six days. A line graph helps us see changes over time easily.
Example 2 — Comparison line graph (Class A vs Class B attendance)
Mon Tue Wed Thu Fri Sat 0 10 20 30 40 50 Class A Class B
Figure: Comparison line graph of attendance for Class A and Class B across six days.
Quick summary: Line graphs are the most common in this chapter. We can also use them for comparison, such as comparing attendance of two classes over the same period.

Designed & Developed by Zahid Qayoom