What does it mean when a sample measurement falls within the control limits in a manufacturing context?

When a sample measurement falls within the control limits in a manufacturing context, it signifies that the process is stable and under control, suggesting consistency in product quality. This means that variability is maintained within acceptable thresholds, allowing for reliable predictions about the manufacturing process.

In this context, while the idea of each unit being "good enough to sell" may sound appealing, it does not fully encompass the implications of falling within control limits. Instead, understanding that variability is controlled is more accurate as it directly relates to the behaviors of the manufacturing process. Controlled variability ensures that products meet predefined quality standards, thus enhancing the likelihood of yielding acceptable products.

Therefore, the concept of controlled variability supports the overall reliability of the manufacturing process without implying that every single article produced can be guaranteed as acceptable just because it falls within those limits. This understanding is central to quality assurance and continuous improvement practices in manufacturing environments, emphasizing the stability of the process overall rather than the absolute quality of individual units.