Sarah Soliz,Director of Quality Programs,is designing and R charts for the rod shearing process at Stockton Steel.She has 26 samples of rod length,and each sample included measurements of 5 rods.The mean of the 26 sample means is 112 centimetres,and mean of the 26 ranges is 0.15 centimetres.The centerline for her R chart is ___.
A)0.15
B)26
C)5
D)112
E)15

Question

Quizplus · Accepted Answer

The centerline for the R chart is the mean of the sample ranges, which is given as 0.15 centimetres in the question. Therefore, the correct choice is A). The mean of the sample means (112 centimetres) is not used in determining the centerline for the R chart. The sample size (5) and the number of samples (26) are used in calculating the control limits for the R chart, but not the centerline. So choices C) and B) are incorrect. There is no relevance of choice D) (112) or choice E) (15) in this context.

Sarah Soliz,Director of Quality Programs,is Designing and R Charts for the Rod