how di i get the UCL LCL

You need to get the USL and LSL from the customer first.  Then quantify your process variation, and set your control limits accordingly.
Ex:  Customer USL is 1000, your variation is +/- 100, your Control limit should be 900.
This is a very simplistic explanation, but take this idea back to your training material for more detail.

NO mrmhead. NO!(UCL,LCL) and (USL,LSL) are unrelated to eachother: any pairs can be possible and if you know one of them you have ‘no’ info about the second one.
What Production likes is for (UCL,LCL) to be inside (USL, LSL); then the process can perform well compared to what the customer wants.
(UCL,LCL) is calculated from process data to determine what the process considers the area where it will vary inside if there are only common causes happening. The calculation is often automatically done by software and the formula’s used depend on the type of control chart. Sorry Coletta, I don’t know the formula out of my head. Either get them from the help of a software package, from your course material or Google on “Shewhart-rules”.
(USL,LSL) are ‘just a wish’ from the customer: “I want my product like that!” Since the customer generally is considered King you try to delever this to him. And if you can’t you start improvement actions (or decide that losing that customer is okay).
What MrMHead mentions I have seen used before where people: 1>Start with the USL, 2> ‘Determine’ the long-term variation and then 3> calculate what their wished for UCL should be maximally. The same for LCL. And then they start improving their Common Variation until they get UCL and LCL as needed for that customer.
Remi

Remember, a customer may be a downstream process that MUST have controlled input.
As stated by others, the calculations for these limits are pretty simple and are in many texts. You should see this in 6 Sigma training.
In consideration of real life situations, let me suggest that you look at the inputs that cause the wait time and spend your time controlling them. I.e. If Wait Time is out of control (and I would say that it is from glancing at your data), then what will you do? Look for independent variables/inputs to control.

UCL – 75.2209 
LCL – 1.55501
There are no points out of control – note that you have a right skewed distribution (makes sense since you are naturally bounded on the left).

Stan,
Best get out your old test books..you missed the UCL and LCL by a considerable amount.
 
 

Humm, Wait time, I wonder how that is distributed? The reason you got the negative number is you did not consider that
this distribution is skewed right. Skewed right also means the UCL is
going to be further out than you ImR calculations you and everyone
else is using. Use the right distribution and you will get the right
control limits.

I looked at your data briefly. Since the data is from a rational subgroup it appears is if a lag is present. You can use MINITAB to analyze the lag. With that being done, the correct interval can be used, charted, and the process analyzed. It is typically expected for time interval data to be exponentially distributed. Since your data is not, I would use the Weibull distribution. These data are nearly normal, and the estimates you would in the present form make would be almost useless information at least on the lower end, because it is not possible to get a negative wait time. As the process wait time interval decreases with improvements, data will become more bunched up against the low end (closer to 3 minutes or so) and possibly be exponential. Expect there to be several estimates, over time, as improvements are made.The study of wait times involves queueing theory, and is more complex than what meets the eye.I am not at my computer where I have a stat package for easy, quick analysis. Recall that process averages tend to become normal as the subgroup size increases from 4. With this information, one can use an X bar chart and analyze the standard error to get the UCL & LCL. Analysis of the individuals will yield upper and lower ‘process’ limits.
Hope that helps.

Ziggy honey,
Have you figured out how to do this right yet?

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