When the control chart shows an increase in the standard deviation of the process,the result is referred to as:
A)a trend.
B)a cycle.
C)a level shift.
D)instability.

Question

When the  control chart shows an increase in the standard deviation of the process,the result is referred to as:
A)a trend. 
B)a cycle. 
C)a level shift. 
D)instability.

Quizplus · Accepted Answer

An increase in the standard deviation of the process on a control chart indicates instability, which means that the process is not in statistical control and may be producing varying and/or out-of-control results. This is also known as an "out-of-control signal." A trend refers to a systematic increase or decrease in the data over time, a cycle refers to a periodic fluctuation, and a level shift refers to a sudden change in the average value of the data.

When the Control Chart Shows an Increase in the Standard