Algebra
Lesson 5-7
Vocabulary:
Scatter Plot - A scatter plot is a graph in which two sets of data are plotted as ordered pairs in a coordinate plane.
Positive Correlation - In a scatter plot, as x increases, y also increases.
Negative Correlation - In a scatter plot, as x increases, the y decreases.
Line of Fit - The line of fit describes the trend of the data. Once you have a line of fit, you can find an equation of the line.
Best-Fit Line - The line that most closely approximates the data in a scatter plot.
Linear Interpolation - The use of a linear equation to predict values that are inside of the data range.
Examples:
1. these graphs show a positive and negative correlation
2. Draw a scatter plot for this table:
ok, so its not exactly a GREAT scatter plot, but it works!
3. Draw a line of fit for the scatter plot
Negative Correlation Line of fit for a negative correlation
Which graph is the best example of data that shows a negative linear relationship between variable X, and variable Y?
The answer is C because as the X increases, the Y decreases.
It isn't A or D, because they both have no correlation, or they are not related.
It isn't B, because it has a positive correlation.
Additional Information: If it is a positive correlation, the line will have a positive slope. If it is a negative correlation, the line will have a negative slope. If there is no correlation, there will be no slope.
Online resources: glencoe.com, Extra Examples
Pictures: 
This page by: AS, Tavia Buysse CK, Amanda Tate