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. What is the upper control limit for this R chart?
A) 10.66
B) 9.37
C) 7.98
D) 6.34

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. What is the upper control limit for this R chart?
A) 10.66 
B) 9.37 
C) 7.98 
D) 6.34

Quizplus · Accepted Answer

The upper control limit (UCL) for an R chart is calculated using the formula UCL = D4 * R-bar, where D4 is a constant that depends on the sample size, and R-bar is the average range. The choice A) 10.66 is likely the correct UCL based on the given options and typical values for D4.

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