Scatter Plot Diagram in Excel
Scatter plot diagrams are used to evaluate the correlation or cause-effect relationship (if any) between two variables (e.g., speed and gas consumption in a vehicle).
When you think there's a cause-effect link between two indicators (e.g., calories consumed and weight gain) then you can use the scatter plot to prove or disprove it. If the points are tightly clustered along the trend line, then there's probably a strong correlation. If it looks more like a shotgun blast, there is no correlation.
Here is an example of a scatter plot diagram created using the QI Macros SPC Software.
If the R² correlation of determination (square of the correlation coefficient) from the scatter plot is greater than 0.8, then 80% of the variability in the data is accounted for by the equation. Most statistics books imply that this means that you have a strong correlation. R2 close to 1.0 means a perfect fit.
- Watch video showing how to create a Scatter Plot in Excel using the QI Macros
- Scatter Plot Examples
- Scatter Plot Matrix for more than two variables