The term correlation is used when two factors, such as characteristics, events, or data, influence each other or are dependent on each other, meaning they are in an interrelationship. Changes in one factor can result in positive or negative effects on other related factors. Therefore, it is important to identify these interrelationships in product planning and problem analysis to ensure quality. A correlation coefficient can be used to determine whether a correlation exists, its type (positive/negative) and its strength. A correlation diagramis one of the tools used for graphical representation.