Random Samples of Four Items Are Selected from a Manufacturing

question 10

Multiple Choice

Random samples of four items are selected from a manufacturing process at regular intervals and a certain quality characteristic is measured. After 25 samples,ΣX = 15,350 and ΣR = 411.4. To construct a mean chart,what is the value for R-bar used to compute the limits?

• A)411.4
• B)614
• C)16.46
• D)102.88