Charts and graphs can organize complex information visually, making it easier to understand. A good graph can quickly communicate what might take several complex sentences to communicate using text only. For example, read the short paragraph below:
Now, look at the same information, but with the numerical data represented as a chart:
Did you read the whole paragraph, or did you just skip down to the chart? The chart makes it much easier and faster to understand the numbers and how they relate to each other.
Let's dive in a little bit and learn some of the basics of reading charts and graphs. There are many kinds of charts and graphs, but we'll focus on the ones you're likely to encounter most often. They include:
Pie charts are used to show how a whole is divided into different parts. For example, this pie chart below shows how a business' budget (whole) is allocated to the different departments (parts):
As you can see, "Operations" takes up the largest portion of the budget at 34%, followed by "Management" at 23%. Can you identify the department(s) with the smallest budget allocation?
Bar graphs (along with other types of graphs) have two axes: One line that runs along the bottom, and one line that runs up the side. The bottom line is called the horizontal or x-axis and is read from left to right. The line that runs top-to-bottom is called the vertical, or y-axis and is read from bottom to top. Each axis will contain either numbers or categories.
Recall our example with Emma and her coffee booth. The graph showing the survey results data was a bar graph. Here it is again:
You can see the number of respondents on the y-axis and the different categories of responses along the x-axis. In this chart, we can see that most of the survey respondents overwhelmingly prefer unflavored coffee to vanilla or hazelnut. Can you tell whether more people preferred hot or iced coffee?
Line graphs are typically used to show trends over time. Line graphs also have x and y axes, but each point indicates a specific value which are then joined together in a line. Here is an example of a line graph showing quarterly sales figures for a business:
In this line graph, things aren't looking good for sales! Notice the steep trend downward from the 1st quarter to the 4th!
A pictogram is a lot like a bar graph, only it uses pictures to represent numbers. For example, the pictograph below shows how much coffee Emma sold at the Fall Festival:
It's important to look carefully at pictographs so that you can understand what the pictures represent. In this case, each icon represents 10 cups of coffee sold, and this is indicated by the key in the lower left corner. So it looks like Emma sold 70 cups of coffee on Thursday. Can you determine how many she sold on each of the other days?