Question

The drive-up window at a local bank is searching for ways to improve service. One of the tellers has decided to keep a control chart for the service time in minutes for the first four customers driving up to her window each hour for a three-day period. The results for her data collection appear below:

Customer	TIME
	9 am	10 am	11 am	12	1 pm	2 pm	3 pm	4 pm
1	1.4	3.8	3.6	4.3	4.0	1.3	0.9	4.7
2	2.3	5.2	2.5	1.2	5.2	1.1	4.4	5.1
3	1.9	1.9	0.8	3.0	2.7	4.9	5.1	0.9
4	5.1	4.8	2.9	1.5	0.3	2.3	4.6	4.7
Customer	TIME
	9 am	10 am	11 am	12	1 pm	2 pm	3 pm	4 pm
1	2.8	0.5	4.5	0.6	4.8	2.7	4.2	0.9
2	3.0	2.7	1.9	1.2	2.8	2.0	1.1	4.4
3	4.1	4.7	4.2	2.7	1.1	2.6	4.4	0.6
4	4.8	3.6	0.4	2.5	0.4	2.6	3.1	0.4
Customer	TIME
	9 am	10 am	11 am	12	1 pm	2 pm	3 pm	4 pm
1	0.3	3.5	5.2	2.9	3.3	4.0	2.8	0.6
2	2.4	3.4	0.3	1.9	3.7	3.3	0.7	2.1
3	5.0	4.6	2.4	0.8	3.8	5.0	1.6	3.3
4	0.9	3.3	3.9	0.3	2.1	2.8	4.6	2.7

Using Minitab:

1. Construct the X-bar and R charts?
2. Estimate the standard deviation for the time to service a customer at the drive-up window?
3. Determine whether there are any indications of a lack of control?
4. If the upper specification of the time to service is 6 minutes and the lower specification is 2.5 minutes, using the process parameters estimated from the control charts generate by Minitab the six pack capability analysis?

if it's possible i need the minitab file or link for it

Answer 1

The Xbar chart is:

The R chart is:

The standard deviation for the time to service a customer at the drive-up window is 1.566.

There is no indication of a lack of control.

The control charts generate by Minitab using the six-pack capability analysis is:

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