These pages are here to introduce you to graphing data. They are not intended to be all-encompassing so look at the instructions in your lab manual and follow your lab instructor’s instructions.

• Example 1: This plots mass as a function of volume for water as measured in a graduated cylinder. It shows the basic parts of a graph.
• Example 2: This plots the absorbance of a colored solution as a function of concentration. The slope is used to calculate a value for the x-variable when given the y-variable.
• Example 3: Pressure and volume are plotted for a sample of hydrogen gas. Are they directly proportional to each other?
• Example 4: Even when there is a direct relationship between the data, it isn’t necessarily easy to find the proper relationship. Kinetics data is analyzed for the thermal decomposition of ascorbic acid (vitamin C).
• Example 5: How do you recognize data that are outliers? In other words, how do you know when to exclude data?
• Example 6: It’s not enough to simply graph the data and report the results. You need to develop the ability to analyze the results and determine if they are reasonable.

There are a few things that can be done with the Linear Regression page:

• You can plot your data and see what it looks like.
• You can have the best-fit line drawn for your data and get the values for the slope and y-intercept.
• You can selectively remove one or more pieces of data and see how excluding that data affects your best-fit line.