Understanding Line Graphs

What does the line in a line graph represent?

How did Joe's performance change over the course of the week?

On which day did Joe get 15 correct math problems?

What is the purpose of drawing an imaginary line straight up from the x axis?

What can we conclude about Joe's math skills by the end of the week?

What can we infer about Joe's math ability from the line graph?

What happens to the cost of the cell phone plan as the number of minutes increases?

Why does the cost of the cell phone plan increase after 250 minutes?

What is the implication of the line graph for Joe's future math ability?

Why did the person in the real-world scenario decide to take the cell phone plan?

A line graph is a graph with a line connecting data points, which can be straight, curved, or look like a connect-the-dots line.
Line graphs provide useful information once you know how to read them.

To read a line graph, locate the point on the x-axis, draw an imaginary line up, and then look where it crosses the actual line to find the corresponding value on the y-axis.
Example: Day 1 on the x-axis, draw an imaginary line up, and it crosses the actual line at 1 on the y-axis, indicating 1 correct math problem.

Interpreting data from a graph involves understanding what the numbers tell us about the situation or person.
A line that gets higher and higher indicates an increase in the measured quantity (e.g., correct answers in a minute).
A curved line indicates a gradual increase or decrease.

Line graphs can be used to make informed decisions in real-life scenarios, such as choosing a cell phone plan.
Example: A line graph showing the cost of a cell phone plan helps determine the cost of going over the allotted minutes.
Interpreting the graph can help determine whether a plan is suitable based on individual needs.