One of the primary objectives of constructing an X-Y Diagram is to separate the vital few X’s from the trivial many X’s.

The statement is correct. The X-Y Diagram, also known as a Cause and Effect (C&E) Matrix, is a core prioritization tool used in the Measure and Analyze phases of the DMAIC (Define, Measure, Analyze, Improve, Control) methodology. Its primary function is to systematically evaluate the relationship between process inputs (the X's) and process outputs (the Y's). By scoring the impact of each input on the critical outputs, the matrix generates a ranked list of inputs. This ranking allows the project team to distinguish the "vital few" inputs that have the most significant influence on the process outcome from the "trivial many" that have little to no effect, thereby focusing improvement efforts effectively.

B. False: This is incorrect. The fundamental purpose of the X-Y Diagram is to apply a structured, data-informed approach to prioritization, which is precisely what "separating the vital few from the trivial many" describes.

1. Kubiak, T. M., & Benbow, D. W. (2017). The Certified Six Sigma Black Belt Handbook (3rd ed.). ASQ Quality Press. In Chapter 12, "Measure Phase," the section on the Cause-and-Effect (C&E) Matrix states its purpose is to "prioritize a list of potential x’s for further investigation" and "identify the 'vital few' x’s that have the most impact on the y" (p. 215).

2. Montgomery, D. C. (2020). Introduction to Statistical Quality Control (9th ed.). Wiley. Chapter 1, Section 1.4.2, "The DMAIC Process," discusses the Analyze phase where "the key variables that are most likely to create process variation are identified." The X-Y Matrix is a key tool for this identification and prioritization step.