How to Create a Line Graph

Hey guys. Welcome to this Mometrix video on how to plot a line graph.

What is a Line Graph?

First things first. What is a line graph? A line graph is a type of chart that helps you to visualize the relationship between two variables. Most often it is the rate of change over time.

You may also have multiple sets of data graphed on one line graph if the same two variables are related.

How to Make a Line Graph

So now, how do you actually make a line graph?

Well, first start by drawing a cross on your paper or whatever you are writing on. The two separate lines represent your $x$ and $y$ axes. The $x$ axis is the line that runs horizontally, and the $y$ axis is the line that runs vertically. Always label your axes!

Next, you need to identify which portion of your data goes on which axis.

So like in this set of data, which column would go on which axis?

 
Your independent variable should always be on the $x$-axis, and your dependent variable should always be on your $y$-axis.

Often times when working with graphs the data you are given is dealing with the rate at which something changes over time. Well, this makes it easier for you to identify your dependent and independent variables. Because time is always independent. You can’t do anything to affect time. You’re constrained by it.

However, like with our data in this case, we can affect the growth of a tree within a given amount of time by manipulating certain variables like soil, fertilizer, catalysts’, temperature, and so on.

So, for this set of data we know that time is our independent variable, so it goes on the $x$-axis, and the “height of the tree” is our dependent variable, so it goes on the $y$-axis.

I hope that this video was helpful.

See you next time!

Line Graph Practice Questions