Scattergraph

 A scattergraph is a graph that shows whether two variables have a relationship; this relationship is called a correlation. It could be used to figure out, for example, how CO2 correlated with temperature to determine whether Global Warming was occurring. There are three types of possible correlations that you can obtain by doing a scattergraph: a positive correlation, a negative correlation, and no correlation. A line of best fit is used to show these correlations. It is a line on a scattergraph that can be drawn near the points on the graph to show the trend between two sets of data more clearly.
 * Scattergraph **

**Positive Correlation**  A positive correlation is when many points on a scattergraph move up to the right. Essentially, both variables increase. Example: The temperature is on the y-axis (vertical axis) of a graph and CO2 levels is on the x-axis (horizontal axis). The graph shows the correlation of the temperature to the CO2 levels. To make the correlation positive, the temperature has to increase as the CO2 levels increase. A line of best fit can be drawn to show a positive correlation.

**Negative Correlation**  A negative correlation is when many points on a scattergraph move down to the right. Generally, one variable increases while the other decreases. Example: The temperature is on the y-axis (vertical axis) of a graph and CO2 levels is on the x-axis (horizontal axis). The graph shows the correlation of the temperature to the CO2 levels. The graph shows the correlation of the temperature to the CO2 levels. To make the correlation negative, the temperature has to decrease as the CO2 levels increase. A line of best fit can be drawn to show a negative correlation.

**No Correlation**  No correlation occurs when many points on a scattergraph have no general pattern. It looks like a scatter of points with no set direction (positive or negative). Example: The temperature is on the y-axis (vertical axis) of a graph and CO2 levels is on the x-axis (horizontal axis). The graph shows the correlation of the temperature to the CO2 levels. The graph shows the correlation of the temperature to the CO2 levels. To have no correlation, the temperature can increase and decrease and the CO2 levels can increase, as long as the result is a random scatter of points where only a horizontal line of best fit can be drawn to show no correlation.

Correlation does not imply causation  It should be made clear though that just because there is correlation, that does not imply that there is causation. 