### Excel Graph Types

There are many graphs or charts available in spreadsheet programs such as Excel and each has it own uses. The links below lead to information about the different Excel graphs and their uses.

### Bar Graphs

Bar graphs are one of the most common types of graph used to display data. Sometimes known as "column charts", bar graphs are most often used to show amounts or the number of times a value occurs.

The amounts are displayed using a vertical bar or rectangle. The taller the bar, the greater number of times the value occurs.

For example, for a school class you can use a bar graph to show and compare the number of students with different hair colors. The more students with a particular hair color, the taller the bar for that color will be in the graph.

Bar graphs make it easy to see the differences in the data being compared.

For more information, read the Excel Column Chart Tutorial or how to Create a Bar Graph in Excel 2003.

### Line Graphs

Line graphs are often used to plot changes in data over time, such as monthly temperature changes or daily changes in stock market prices.

They can also be used to plot data recorded from scientific experiments, such as how a chemical reacts to changing temperature or atmospheric pressure.

Similar to most other graphs, line graphs have a vertical axis and a horizontal axis. If you are plotting changes in data over time, time is plotted along the horizontal or x-axis and your other data, such as rainfall amounts is plotted as individual points along the vertical or y-axis.

When the individual data points are connected by lines, they clearly show changes in your data - such as how a chemical changes with changing atmospheric pressure. You can use these changes to predict future results.

For more information, read the Excel Line Graph Tutorial

### Scatter Plot Graphs

Scatter plot graphs are used to show trends in data. They are especially useful when you have a large number of data points. Like line graphs, they can be used to plot data recorded from scientific experiments, such as how a chemical reacts to changing temperature or atmospheric pressure.

Whereas line graphs connect the dots or points of data to show every change, with a scatter plot you draw a "best fit" line. The data points are scattered about the line. The closer the data points are to the line the stronger the correlation or affect one variable has on the other.

If the best fit line increases from left to right, the scatter plot shows a positive correlation in the data. If the line decreases from left to right, there is a negative correlation in the data.

### Excel Pie Charts

Pie charts, or circle graphs as they are sometimes known, are a little different from the other three types of graphs discussed.

For one, pie charts do not use horizontal and vertical axes to plot points like the others. They also differ in that they are used to chart only one variable at a time. As a result, it can only be used to show percentages.

The circle of pie charts represents 100%. The circle is subdivided into slices representing data values. The size of each slice shows what part of the 100% it represents.

Pie charts can be used anytime you want to show what percent a particular item represents of a data series such as:

- A baseball player's batting average can be shown with a pie chart as it represents the percentage of hits when compared to his total number of at bats for a season.
- A company's profits for each month can be shown with a pie chart as a percentage of the year's total profits.

For more information, read the Excel Pie Chart Tutorial