Scatterplot

A scatter plot is a graph made by plotting ordered pairs in a coordinate plane to show the correlation between two sets of data. The value of one variables determines the position on the horizontal axis and the value of the other variable determines the position on the vertical axis. The example below has two pieces of information (years of experience and income) - these are the two variables that determine if a relationship exists.  X represents experience and Y represents income. Notice how the line drawn through the data points has an upward slope.  This slope represents the direction of the relationship and tells us that as experience increases so does income.

http://allpsych.com/researchmethods/correlation.html