
e Classic Seven Quality Tools • 79
SCATTER PLOT
Scatter plots, also known as scatter diagrams, are used to analyze possible
relationships between paired data (Ishikawa, 1991), such as temperature in
producing steel and the resulting hardness of the steel. A scatter plot can
indicate strong or weak positive or negative correlations or the absence of
a correlation. A correlation does not necessarily mean that the two factors
are related; they could be independent of each other and related to a third
factor (George et al., 2005).
Key Points
• Scatter plots indicate possible relationships between paired data.
• A correlation may be the result of an ...