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

Multiple Choice

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 R chart to see if the variability in production times is in-control.What is the center line of this R chart?

A) 4.8
B) 6.0
C) 6.9
D) 7.1