What method is used to separate the variation of a measurement process?

A measurement capability study is the correct choice for separating the variation of a measurement process. This method focuses on quantifying how well a measurement system can produce results that meet specified requirements. In a capability study, both the inherent variability of the measurement system and the variation due to the process being measured are assessed. This helps identify sources of variation, enabling practitioners to understand and control them better.

In contrast, a sample size analysis primarily addresses the number of observations required for statistical validity and does not specifically break down measurement variation. A control chart analysis is used for monitoring process stability over time and identifying trends or shifts in the data but does not directly focus on separating measurement variation. A correlation assessment deals with the relationship between two variables but does not provide insights into the variation within a measurement process itself. Thus, the measurement capability study stands out as the method dedicated to understanding and managing the variation inherent in measurement systems.