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EQC7016 STATISTICAL METHODS FOR QUALITY MANAGEMENT

Sem 1 2020/2021

ONLINE TEST 1 (2 hours)

Question [DatasetQ]

Customer waiting times of teller service at IM bank during the 12:00 noon to 1:00 pm lunch hour have been recorded, in minutes, for a subgroup of four customers (one at each 15-minute interval during the hour). Waiting time is measured from the point each customer enters the line to when he/she reaches the teller window. The results over the four-week  period are stored as DatasetQ.

(a) Briefly describe how waiting time can be used as measuring the teller service of the bank branch? (2 marks)

(b) State the type of control chart to be applied for the dataset. (2 marks)

(c) For subgroups of n = 4, what is the d2  and D2 factor in the control charting scheme? (2 marks)

(d) For the four-week period, is the waiting time process in statistical control? Plot the type of control chart in (b). (5 marks)

(e) What do you understand by the phrase “the process is statistically in-control”? (4 marks)

(f)  Differentiate Phase I and Phase II of a control charting technique. (3 marks)

(g) Describe how you can measure the performance of control chart scheme of this case study (Hint: also show how to compute ARL for the control chart in (d)). (7 marks)

(Total: 25 marks)