The data

For this lab, I went to the US Census Bureau website and downloaded population summary data for the United States from 1950-1980.  I saved it in a "comma-delimited" text file (a csv file) and read it into Mathematica using the following command (you will get an error message if you execute it):

So you don't have to worry about importing the data, you should execute the following statement to define our population data:

(I only included the Import function in case some of you want to experiment with importing your own data.)

Let's take a look at what this data looks like:

Notice that we use the ListPlot function to plot discrete data like this.  I explicitly specify the PlotRange to be sure I see everything and I use PlotStyle to set the color and size of the dots.