Six Sigma Green Belt Certification Practice Exam

Which graphical representation of data is also known as a correlation chart?

1. Stem and leaf plot

2. Scatter diagram

3. Pareto diagram

4. Box-and-whisker plot

The correct answer is: Scatter diagram

A scatter diagram is a graphical representation of data that displays the relationship between two quantitative variables. It is particularly useful for identifying correlations or patterns that may exist between those variables. By plotting individual data points on a Cartesian plane, a scatter diagram can clearly show how one variable tends to change as another variable changes, which helps in visualizing the strength and direction of a relationship. A positive correlation can be observed when the points tend to rise together, while a negative correlation is evident when one variable increases as the other decreases. If the points are scattered without any discernible pattern, it may indicate no correlation. This ability to show the relationship between two sets of data is fundamental in statistical analysis, making the scatter diagram invaluable in Six Sigma projects for identifying potential factors impacting process performance. The other types of plots serve specific purposes, such as organizing the distribution of data points, identifying the most significant factors, or displaying the spread of data, but they do not directly convey the relationship between two variables like a scatter diagram does.