Gastala

Stan, if you cannot reply to posts in a professional manner perhaps you should not reply at all. I visit this forum every couple of months and am sick and tired or reading your rude and abusive nonsense. Why don’t you get a life and leave this forum to people who have a genuine interest in Six Sigma.

Could you please send me a copy of the funny lean vid.
Thank you very much,
[email protected]

It is possible that the time is related to the size (value) of the debt.
So you might want to plot these variables against each other initially, then stratify the data.
There may be different root causes associated with different subsets.
There may be one subset that gives the biggest hit.
Nothing profound here but hopefully it helps

I ‘ve just realised the three examples I gave could all be the same persons life

I think you need to log the defects you find at stage 8, then do pareto analysis, then try to find (possible) causes of biggest contributors, etc.
With such a high reject rate you will get data quickly and then you should be able to select one cause for a quick hit solution.
Good luck

Is it technically possible to tell, once a defect is found at stage 8, what stage it originated? Or can any stage create the same defect?
Could some brainstorming and a simple ‘fishbone diagram’ identify the possible causes? they are what you then try to control.

If the consequenses are so serious, I do not think your objective should be to minimise the audit time, it should be to minimise the frequency and/or cost of the errors.
How often do the auditors find an error just now?  What types of error? What are the root causes of these errors?
Also, is the existing audit process 100% effective, or are…[Read more]

What is the source of the formula
Min. Sample Size with 95% confidence level and precision 5% = (1.96/0.05)^2*p(1-p)

I was taught that “inspections are not value add”.  However, on reflection I believe that inspections to check work has been done right must be different from inspections to accurately assess what work needs doing (which is my assumption about aviation inspections.)

Disregard last post – wrong topic!

I’m no expert but have you considered non parametric tests – e.g. Mann-Whitney.  This basically compares the cumulative distributions with each other – regardless of their fit to any standard distribution.

Your proposal implies an increase in some types of defect could be hidden by a decrease in the most heavily weighted defects.
Avoid composite metrics like this. You will never get agreement on the weightings.
You have several types of defect – measure and investigate and reduce them seperately.

What do you do with the information you get from these scales?
Would it matter if it was wrong – if not, why are you weighing anyway?
If it is important in some way, maybe better check the scales now and again.
 

Good advice.  I suspect my problem will be either to
calm down the optimists who want to declare victory after one month of 40 v 30
or
ask for patience from the doom mongers if the first month turns out 36 v 34

How many enquiries are there that did not result in a contract? Is that a big enough sample to do anything with?

Jan,
Thanks again – I think I now have this clear in my head.
Glen

Thanks Jan
For 40 machines x 8 months I have
Power and Sample Size
2-Sample t Test
Testing mean 1 = mean 2 (versus <)
Calculating power for mean 1 = mean 2 + difference
Alpha = 0.05 Sigma = 1.3
Sample
Difference Size Power
-0.25 320 0.7838
-0.17 320 0.5030
So, quoting Minitab
The power of a test is the probability of correctly…[Read more]

Surely ‘approaches zero’ and ‘nearly equivalent’ are only meaningful when compared to some standard of precision.

If you do a search on this forum you will find that it has been discussed extensively over the years and there are any number of views. The upshot seems to be that it is a reasonable rule of thumb where the accuracy is sufficient for most purposes. It is also where you can start to use the z-test instead of the t-test.
From my experience I…[Read more]

Top management are concerned with strategic issues and in many cases regard process improvement as a tactical issue. They see SAP as a strategic investment.
Where Six Sigma has been successful it has been sold to top management as a strategic issue, most notably of course at Motorola and GE.
It does not necessarily follow that top management are…[Read more]