# What are the Different Types of Graphs?

Graphs are helpful tools that writers can employ to help the reader understand the information in a more visual way. There are many different kinds of graphs that have different functions. A line graph highlights changes in amounts. A bar graph highlights the individual amounts. It all depends on what the writer wishes to convey through their use of graphs.

## Graphs

A graph is a common way to present information in a visual format. Here, we have two common types of graphs: the line graph and the bar graph. They’re similar in many ways. Notice that they both have a title, like “Income vs Education”. The title could be something longer, like “A Comparison of Average Income with Levels of Education”, but it still means the same thing. This tile over here is “Money Spent on Groceries Monthly”.

In both types of graphs, you have an x-axis and a Y-axis. The x-axis is the horizontal line. Notice that education is the x-axis and income is the y-axis. Here we don’t have lines drawn, but you can still see the month of the year is the x-axis and the money spent each month is the y-axis, because that’s vertical (it’s up and down). Generally, the x-axis represents the independent variable. That’s the variable that the rider can move around.

Whoever made this graph for education could put “high school”, “bachelor’s degree”, “master’s degree”, “doctorate”, etc. They are setting out the different levels of education. Notice that if there is an independent variable, there also has to be a dependent variable. Whoever is writing something, whoever is constructing a graph, can’t have two independent variables. In other words, they can’t choose what both of the variables are going to end up being.

If they choose high school to be right here, they don’t decide what the income level for high school is going to be. They have to research that and figure out what that is. The y-axis is generally the dependent variable and depends on whatever the independent variable is. The same case is over here. The constructor of this graph set out January, February, March, and April to be plotted along the x-axis, so this is the independent variable.

The dependent variable is the money spent each month. The person who made this graph doesn’t get to decide how much money was spent, because they’re just reporting what was already spent. The difference between these two graphs is just how the information is presented within the graph. Here, we have a line graph, which is basically what it sounds like. It’s a line. These points right here are plotted in different areas.

Say this marker here was high school, that was the level of education, and the income right here is $36,000. There’s a point put right here. This next one is so an associate’s degree. The income level is $54,000. A point is put right there, and then a line is used to connect those two dots. The same goes all the way down with different levels of education. The lines are used to connect the dots to see the general flow how the income level is changing as education changes.

Over here, we see we have a bar graph. For January here, we’re looking at how much money was spent in January. This bar right here is going to raise as high as the amount of money that was spent. Say $80 was spent. Notice here that this bar ends at about the $80 mark. Over here in April, over $200 was spent in that month for groceries. The line exceeds $200 to maybe $240. That’s how that is represented. There are pros and cons to using a line graph or a bar graph.

It really is up to how the writer of the graph wants to present the information. A line graph is generally better for seeing flow over time, to see if something remains constant, or if it rises or falls. A bar graph is more focused just on that particular variable. In January, how much did groceries cost? It’s not so much concerned with comparing the different months. It’s just seeing in February how much money was spent.

If this information was presented in a line graph, the focus should be on the rise and fall of the amount spent on groceries. You would see that January it was down here, then the graph raises up for February, falls for March, and rises again for April. You’re presenting the same information with either graph, but the focus of the information is different.

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Last updated: 07/11/2018