Final answer:
In Statistical Process Control (SPC), if one third of the units produced by a process do not meet customer specifications, it indicates that the process is out of control.
Step-by-step explanation:
In the language of Statistical Process Control (SPC), the statement 'one third of the units produced by a particular process step do not meet customer specifications' indicates that the process is out of control. When a process is out of control, it means that it is not operating within the desired specifications and is producing a high number of non-conforming units.
In order for a process to be considered 'in control', it should meet certain criteria, such as being stable, predictable, and operating within the desired specifications. If one third of the units produced do not meet customer specifications, it is an indication that the process is not meeting these criteria.
Therefore, the correct answer is option b) the process is out of control.