How to Create Bar and Line Graphs

Draw the Axes

Identify the Axes Y- Axis X- Axis

Identify the Axes Y- Axis X- Axis Dependent Variable (what is observed and measured) Independent Variable (what is changed by the scientist)

One way to remember which data goes on which axis is the acronym DRY MIX. D.R.Y. M.I.X. D- DependentM- Manipulated R- Responding I- Independent Y- Y-axisX- X-axis DRY MIX

Title Write an appropriate title for the graph at the top. The title should contain both the independent and dependent variables.

Scale Decide on an appropriate scale for each axis. The scale refers to the min and max numbers used on each axis. They may or may not begin at zero. The min and max numbers used for the scale should be a little lower than the lowest value and a little higher than the highest value. This allows you to have a smaller range which emphasizes the comparisons/trends in the data.

Scale The Y-axis scale is from The largest value though is only 35.

Scale The Y-axis scale is now from This does a better job emphasizing the comparisons between coins.

Intervals Look at your minimum and maximum values you set up for both the Y and X-axis. (For most bar graphs, the X-axis will not have numerical values.) Decide on an appropriate interval for the scale you have chosen. The interval is the amount between one value and the next. It is highly recommended to use a common number for an interval such as 2, 5, 10, 25, 100, etc.

Intervals The interval for the Y-axis is 20. The X-axis does not have numerical data and does not need an interval.

Labels Both axes need to be labeled so the reader knows exactly what the independent and dependent variables are. The dependent variable must be specific and include the units used to measure the data (such as “number of drops”).

Labels DV label IV label

Another handy acronym to help you remember everything you need to create your graphs….. T.A.I.L.S. T itle A xis I nterval L abels S cale TAILS

Title: Includes both variables Axis: IV on X-axis and DV on Y-axis Interval: The interval (4) is appropriate for this scale. Label: Both axes are labeled. Scale: Min and max values are appropriate.

Bar Graphs vs Line Graphs

Bar Graphs Bar graphs are descriptive. They compare groups of data such as amounts and categories. They help us make generalizations and see differences in the data.

Example

Another example

Line Graphs Line graphs show a relationship between the two variables. They show how/if the IV affects the DV. Many times, the IV plotted on the X-axis is time. They are useful for showing trends in data and for making predictions.

Example

Another example

Create-a-Graph Online! Click here Click here to use the online tool!