TABLE 18-3
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 18-3,suppose the analyst constructs an chart to see if the production process is in-control.What is the upper control limit (UCL)for this chart?
A)62.15
B)60.95
C)59.85
D)58.75

Question

TABLE 18-3
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 18-3,suppose the analyst constructs an  chart to see if the production process is in-control.What is the upper control limit (UCL)for this chart?
A)62.15 
B)60.95 
C)59.85 
D)58.75

Quizplus · Accepted Answer

Using the formula UCL = X + 3R/d2, where X is the overall mean, R is the overall range, and d2 is a factor from a table (in this case, d2 = 2.704), we get UCL = 59.85.

TABLE 18-3 A Quality Control Analyst for a Light Bulb Manufacturer Is