Mate, you may very well have saved my assessment from going into the fire, Thank you for your hard work at making such a easy to follow video, it is a mark of a true teacher to make the seemingly complex, simple to follow, Thank you again.
Thank you for the video! Helped me so much. Can you get to the same result without the inputs in chart form? What if I have the dates and values across a horizontal row?
Thank you for the video, but I wanted to point out that this is NOT the correct way to calculate control limits for control charts. In control charting the sigma symbol is not the same as typical standard deviation. It is calculated using different methods (depending on the type of the chart) that takes into consideration the relative shift of the process over time. This is by design and it is very critical that sigma is calculated correctly for a control chart to be useful. In your case, sigma should be calculated as [sigma = MR/d2] .....where MR is the moving range of each successive data point and d2=1.128 (the scalar constant for control charts where sample size is n=1). I encourage people to compare both ways with real data and you will see how much different the values are. Using global standard deviation (as you have) will severely inflate the control limits and can give you the false impression that a process is in control when it is likely not. The reason 3*SD seems too far away is because it’s not the right calculation. Calculating the sigma value correctly will show many of the data points are out of control even with 3*sigma. Apologies for the rant but i see this error too often. Too many MBAs who took a stat class thinking this is what statistical process control is.
I believe for an overview this technique is alright. To see if anything went beyond the 3 standard deviations. But we would love it if you could make a video on calculating it the right way.
I'm struggling to get my head round one thing... why would you want your control limits to be dynamic? Imagine the scenario where you have a data point that should sit just outside your CL. But because the CL is dynamic, it shifts so the new data point is now within the CL. It's kind of a self fulfilling prophecy! Shouldn't you use historical data to establish fixed control limits, then see where new data points fall in relation to those limits? Thanks in advance 🙂
I have 480 time measurements per day for 30 days, if I calculate the average per day and out of this mean, find the standard deviation it would be correct? Should I use x- chart and s-chart or r-chart?
His calculation of the UCL and LCL was WRONG. I followed his method but I lost the points. My professor pointed out the UCL= Mean + 3 * Deviation. 3 TIMES! And LCL needs 3 times too!
Yes you can use 3 times. In practice, I find that way too far. The process always seems to be "in control". So, try it and adjust to suit your situation.
Mate, you may very well have saved my assessment from going into the fire, Thank you for your hard work at making such a easy to follow video, it is a mark of a true teacher to make the seemingly complex, simple to follow, Thank you again.
Literally followed his directions had to pause multiple times but I did it!
Thank you for sharing the video. I was able to put together a QC Chart for a year's worth of data in a few hours.
Thank you. Very easy to follow.
Thanks, it was very useful for my school homework!
Very well explained sir!
Thank you for the video! Helped me so much. Can you get to the same result without the inputs in chart form? What if I have the dates and values across a horizontal row?
Tq, most useful information and good explanation❤
I can not thank you enough for your precise and clear explanation. You really helped me to do my assignment correctly. Thanks
Thank you!
Thanks a lot. Keep doing such excellent knowledge sharing
Great content and always on the mark. I honestly love your videos so helpful and insightful🤧🤩
This is absolute fire
Thank you very much david.
Thank you so much. Really appreciated. Informative video.
Excellent presentation
Thanks..very useful
How are the USL and LSL added into the control chart?
THANK YOU VERY MUCHHHH
Can you please tell me how to make fishbone diagram in excel
Great vid
You are the absolute GOAT!!! You never fail me brother
Thank you for the video, but I wanted to point out that this is NOT the correct way to calculate control limits for control charts. In control charting the sigma symbol is not the same as typical standard deviation. It is calculated using different methods (depending on the type of the chart) that takes into consideration the relative shift of the process over time. This is by design and it is very critical that sigma is calculated correctly for a control chart to be useful.
In your case, sigma should be calculated as [sigma = MR/d2] .....where MR is the moving range of each successive data point and d2=1.128 (the scalar constant for control charts where sample size is n=1). I encourage people to compare both ways with real data and you will see how much different the values are. Using global standard deviation (as you have) will severely inflate the control limits and can give you the false impression that a process is in control when it is likely not. The reason 3*SD seems too far away is because it’s not the right calculation. Calculating the sigma value correctly will show many of the data points are out of control even with 3*sigma.
Apologies for the rant but i see this error too often. Too many MBAs who took a stat class thinking this is what statistical process control is.
Great information, thank you! 👍🙂
I believe for an overview this technique is alright. To see if anything went beyond the 3 standard deviations.
But we would love it if you could make a video on calculating it the right way.
I love this you are doing a very excellent job, keep it up
I'm struggling to get my head round one thing... why would you want your control limits to be dynamic? Imagine the scenario where you have a data point that should sit just outside your CL. But because the CL is dynamic, it shifts so the new data point is now within the CL. It's kind of a self fulfilling prophecy! Shouldn't you use historical data to establish fixed control limits, then see where new data points fall in relation to those limits? Thanks in advance 🙂
Have you found the answer yet?
Thank you :)
Nice job - thank you. I learned some new tricks!
Great resource, how can I contact you?
Thank you very much. It is explained very clearly. Now I know how to impress my director :)
Very useful and professional
This will help me close my audit non compliances.
Very simple, method thank you
This is very helpful 💙
If I understood correctly you UCL and LCL are 1 sigma away from the mean, correct?
Impressive!
I have 480 time measurements per day for 30 days, if I calculate the average per day and out of this mean, find the standard deviation it would be correct? Should I use x- chart and s-chart or r-chart?
Ucl and lcl calculation are wrong...
Ucl -average+3std dev
You are right. In my experience, those values are too big for me (controls too wide). Good call for anyone who needs wider ones though!
His calculation of the UCL and LCL was WRONG. I followed his method but I lost the points. My professor pointed out the UCL= Mean + 3 * Deviation. 3 TIMES! And LCL needs 3 times too!
Yes you can use 3 times. In practice, I find that way too far. The process always seems to be "in control". So, try it and adjust to suit your situation.
Good but too damn fast
moving too fast