Scatter Diagram
The scatter diagram is the simplest of the seven tools and one of the most useful. The scatter diagram is used to determine the correlation (relationship between two characteristics (variables) Goetsch [3].
The shape of the scatter digram often indicates what type of relationship may exist between the two variables. A scatter diagram, shown in Error! Reference source not found., was constructed to find the relationship between water flow used to cool down the steel during various production stages and steel tensile strength using collected data that represent the average for the sample readings per hour for the water flow and tensile strength. The scatter diagrams clarifys that there is no direct relationship exists between tensile strength and water flow.