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 upper control limit for her chart is ___.
A)112.09
B)5.087
C)26.087
D)115.90
E)110.09

Question

Quizplus · Accepted Answer

The upper control limit (UCL) for an R chart is calculated using the formula UCL = D4 * R-bar, where D4 is a constant that depends on the sample size (n=5 in this case). For n=5, D4 is approximately 2.114. Therefore, UCL = 2.114 * 0.15 = 0.3171, which when added to the mean of the sample means (112), gives approximately 112.09.

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