Instruction 18-9 A Quality Control Analyst for a Light Bulb Manufacturer Is

Multiple Choice

Instruction 18-9
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 Instruction 18-9,suppose the analyst constructs an R chart to see if the variability in production times is in control.What is the lower control limit for this R chart?

A) 4.84
B) 2.98
C) 1.34
D) 3.37