Consider a service process such as a fast food drive through window. The target for a customer's waiting time is 3.0 minutes. A manager observes the process and randomly collects a sample of four waiting times each hour over a 12 hour period. The sum of the average waiting time for each of the 12 samples is 35.4. The sum of the range for each of the 12 samples is 18.0 The centerline for the process control chart reporting variability between the sample means is
A) 2.85
B) 2.95
C) 3.00
D)3.05

Question

Consider a service process such as a fast food drive through window. The target for a customer's waiting time is 3.0 minutes. A manager observes the process and randomly collects a sample of four waiting times each hour over a 12 hour period. The sum of the average waiting time for each of the 12 samples is 35.4. The sum of the range for each of the 12 samples is 18.0 The centerline for the process control chart reporting variability between the sample means is
A) 2.85
B) 2.95
C) 3.00 
D)3.05

Quizplus · Accepted Answer

The centerline for the process control chart is the average of the sample means. The sum of the average waiting times for the 12 samples is 35.4, so the average is 35.4 / 12 = 2.95.

Consider a Service Process Such as a Fast Food Drive