Final answer:
A process is often considered out of control in statistical process control if there is a run of eight or more sample points either all above or below the center line, or seven in a row either increasing or decreasing, although this rule can vary by industry or desired sensitivity.
Step-by-step explanation:
The question pertains to the process control aspect of statistics, specifically in determining when a process is out of control based on sample values. In statistical process control (SPC), a run of eight or more sample points on a control chart either all above or all below the center line (or any similar rule of thumb, like seven in a row increasing or decreasing) is often considered evidence that a process is out of control. The exact number can vary depending on the industry standards or the sensitivity required for the particular process being monitored.
To determine if a process is out of control, statistical tests are applied to the data. These involve looking at the sequence and pattern of plotted points (sample values) on a control chart. If there is a steady increase or steady decrease of certain number of consecutive points, it might indicate a non-random pattern suggesting a shift in the process' behavior. This can be influenced by the inherent variability of the data and the temporal or spatial scales examined.
An important aspect of process control is understanding that when variables like resistance are modified, they affect the steady state of a system. For instance, increasing resistance in an electrical circuit can alter how rapidly or slowly the circuit reaches its steady state.