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 range chart, what is the upper control limit (UCL) for the range?
A) 37.553
B) 411.4
C) 0.00
D) 102.85

Question

Quizplus · Accepted Answer

The UCL for a range chart is calculated using the formula UCL = D4 * R̄, where D4 is a constant that depends on the sample size (n=4, D4=2.282) and R̄ is the average range (ΣR/number of samples = 411.4/25 = 16.456). Therefore, UCL = 2.282 * 16.456 = 37.553.

Random Samples of Four Items Are Selected from a Manufacturing