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

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

Quizplus · Accepted Answer

The centerline for the R chart is calculated as the mean of the sample ranges. In this case, the mean of the 26 ranges is given as 0.15 centimeters, so the centerline for the R chart should be 0.15. Therefore, the correct answer is A) 0.15.

Sarah Soliz, Director of Quality Programs, Is Designing and R