7.1. Line Graphs and Scatter Plots http://www.ck12.org
TABLE7.1:
Time Worked (Hours) Money Earned
0 $0
1 $9. 00
2 $18. 00
3 $27. 00
4 $36. 00
5 $45. 00
6 $54. 00Now that the points have been plotted, the decision has to be made as to whether or not to join them. Between every
two points plotted on the graph are an infinite number of values. If these values are meaningful to the problem, then
the plotted points can be joined. This data is calledcontinuous data. If the values between the two plotted points
are not meaningful to the problem, then the points should not be joined. This data is calleddiscrete data. In the
above problem, it is possible to earn $4.50 for working one-half hour and this value is meaningful for our problem.
Therefore the data is continuous and the points should be joined.
Now you know how to graph a straight line from a table of values. It is just as important to be able to graph a
straight line from a linear function that models a problem. The equation of a straight line can be written in the form
y=mx+b, wheremis the slope of the line andbis they−intercept.
Example 2:Draw a graph to model the linear functiony= 2 x+ 5