You are a life saver. I have a huge test tomorrow and I could not for the life of me figure out even what each of the symbols meant from my teachers notes. thank you dude

@greenbeltacademy

10 ай бұрын

You're welcome!!

Brilliant. Thank you so much for the proper and easy way to simplify the calculation of variance and standard deviation in both population and samples.

Super clear. Easy to follow. Thank you!

You are more helpful than my college instructor. Thank you!!!

@CQEAcademy

Жыл бұрын

Thanks Nate!

Hi Andy I really like your sessions and its building my confidence to face my CQE exam. Thank you so much!

@andyrobertson566

2 жыл бұрын

You're absolutely welcome Garima!!

This is great video!!! Standard Deviation and Variance are the key elements in Statistics. Knowing or understanding these concepts would help one to deal or handling big data samples easily. Thanks for sharing this with us!!!

@CQEAcademy

3 жыл бұрын

You're welcome Daniel, and I totally agree, standard deviation is one of the most important concepts in statistics!! -Andy

This video showed me a lot!! Thanks for taking the time to make these its been a great resource

@CQEAcademy

2 жыл бұрын

You're welcome Luis!!!

Excellent Andy I know this but I enjoyed how you taught it as this is how I taught suppliers employees how this works by pen. There are calculator that do this for us, but to know what to do is priceless.

@andyrobertson566

2 жыл бұрын

Thanks Harold!!!!

Very nicely explained

Anyone helps me with this please. Suppose a sample of n = 74 observations was taken and the sample variance was calculated to be 1011.24. What is the sample standard deviation? Where relevant, round your answer to three decimal places. To obtain standard deviation, we just need to take the square root of the variance. Does n = 74 have anything to do with the calculation of standard deviation?

Wow. Straight forward 👌👌

@CQEAcademy

Жыл бұрын

You're absolutely welcome!!!!!

Thank you very much for sharing this vedio 🌹

@CQEAcademy

2 жыл бұрын

Thanks Mahgoub!!!

Thank you very much for this video. I would like yo ask why we devide by N-1 and not N when calculating s for samples?

@greenbeltacademy

Жыл бұрын

Great question, so the bottom half of that equation is the degrees of freedom, and when dealing with a sample of data, the degrees of freedom is equal to N-1. Explaining why its N-1 is probably an entire video on its own!

Hi Andy. Thanks for sharing. But just curious, is scientific calculator not allowed in US's CQE exam? If we key in all the figures in a scientific calculator, then we can get the variance in less than a minute.

@CQEAcademy

Жыл бұрын

Hey Amin, that's a great question, and no, calculators like that (scientific calculators) where you can just plug in numbers and ask the calculator to give you the standard deviation are usually not allowed on the exam. The calculator I usually recommend to my students is the TI-30X are any calculator like that

You should explain why the values are squared.

Perfect

@CQEAcademy

2 жыл бұрын

Thanks!

Hello Andy, What is difference between standard deviation overall and within, How this was calculated from sample data. Minitab is showing the both value when we perform analysis. Can you please give some clarification on this

@CQEAcademy

10 ай бұрын

Great question, if you get data from a control chart, it can estimate the standard deviation of a process from R-bar, which is the variation within each subgroup.

@ratnasekharchatragadda3695

10 ай бұрын

Hi Andy, Thanks for your reply. I did analysis for 253 samples with no subgroup and only LSL, no USL. Hence, we obtained Cpk: 2.17 and Ppk: 0.82. How can I interpret these results? I was perplexed by how to interpret the results. plz

@greenbeltacademy

10 ай бұрын

@@ratnasekharchatragadda3695 in that instance, I would use the Ppk value. When you graph your data on a histogram, and overlay the specification, does the spec limit appear to be within 2-3 standard deviations of the mean value? If so, 0.82 would be correct.

@ratnasekharchatragadda3695

10 ай бұрын

​@@greenbeltacademy: Hi Andy, I really needed a lot of enlightenment. On one side, the 3 Sigma specification limits are overlaid on the histogram. another side no. Anyhow, can you please recommend any videos to better understand the same? Also, can you please share your email ID so I can share the data with you to perform analysis at your end?​

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