The capability of a process that uses discrete data is expressed using all of the following except which?

The capability of a process that uses discrete data is often assessed through various metrics that quantify the performance and quality of that process. PPM defective, defects per unit, and percent defective are all measures that relate directly to discrete data, as they focus on counting the number of defects in a batch or lot of items.

PPM defective refers to the number of defective parts per million units produced, which provides a clear and quantifiable metric for assessing the quality of a manufacturing process. Defects per unit measures how many defects occur on average per unit, and percent defective indicates the proportion of items that are found to be defective.

On the other hand, Cp and Cpk are metrics used to assess process capability but are applicable primarily to continuous data. These indices measure how well a process conforms to its specifications based on variability and mean, which requires continuous measurement data to determine how much variation exists in the process and how it relates to the specification limits. Therefore, these two metrics are not suitable for processes characterized by discrete data, making them the exception in this context.