TABLE 17-3
A quality control analyst for a light bulb manufacturer is concerned that the time it takes to produce a batch of light bulbs is too erratic. Accordingly, the analyst randomly surveys 10 production periods each day for 14 days and records the sample mean and range for each day.

-Referring to Table 17-3, suppose the analyst constructs an R chart to see if the variability in production times is in-control. The R chart is characterized by which of the following?
A) Increasing trend
B) Decreasing trend
C) In-control
D) Points outside the control limits

Question

TABLE 17-3
A quality control analyst for a light bulb manufacturer is concerned that the time it takes to produce a batch of light bulbs is too erratic. Accordingly, the analyst randomly surveys 10 production periods each day for 14 days and records the sample mean and range for each day.
 
-Referring to Table 17-3, suppose the analyst constructs an R chart to see if the variability in production times is in-control. The R chart is characterized by which of the following?
A) Increasing trend 
B) Decreasing trend 
C) In-control 
D) Points outside the control limits

Quizplus · Accepted Answer

The R chart is characterized as "in-control" because there are no points outside the control limits, and no obvious increasing or decreasing trends. This suggests that the variability in production times is consistent and predictable.

TABLE 17-3 A Quality Control Analyst for a Light Bulb Manufacturer Is