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Standard Deviation & Degrees of Freedom Explained | Statistics Tutorial | MarinStatsLectures
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- čas přidán 18. 06. 2018
- Standard Deviation and Degrees of Freedom: What is Standard Deviation? What is Degrees of Freedom in Statistics with Examples! (Best Explanation!)
To Calculate Standard Deviation with R:(goo.gl/5P2LBY)
👍🏼 Best Statistics with R Programming Language:( goo.gl/4vDQzT )
▶︎ In this statistics video tutorial you will learn the underlying concept of the Sample Standard Deviation, and what it is actually measuring. We will also explain the concept of the Degrees of Freedom and why do you divide by (n-1)?
▶︎ Standard deviation gives us a measure of how far individual observations tend to move (or deviate) away from the mean, on average. In other words, on average how far does an observation tend to get from the mean? It is not quite the average deviation, but we can think of it that way conceptually.
▶︎ While we present the standard deviation formula, the focus is on the concept of what the standard deviation is attempting to summarize. We believe this to be one of the best explanations of standard deviation that you will see.
◼︎ Table of Content:
0:00:12 Introducing Standard Deviation with example
0:00:29 Standard Deviation Formula: Step by Step
0:01:37 the Average Absolute Deviation formula
0:03:06 Average Absolute Deviation formula vs Standard Deviation?
0:03:23 The Non-smooth functions of X versus the absolute value of X and how to fix it (squaring the deviations)
0:07:08 Degrees of Freedom explained: Why do we divide by (n-1) in the standard deviation formula
►► Watch More:
► Statistics for Data Science (Complete Series): bit.ly/2SQOxDH
►Data Science with R(Complete Series): bit.ly/1A1Pixc
►Getting Started with R (Series 1): bit.ly/2PkTneg
►Graphs and Descriptive Statistics in R (Series 2): bit.ly/2PkTneg
►Probability distributions in R (Series 3): bit.ly/2AT3wpI
►Bivariate analysis in R (Series 4): bit.ly/2SXvcRi
►Linear Regression in R (Series 5): bit.ly/1iytAtm
►ANOVA Concept and with R Videos: bit.ly/2zBwjgL
►Hypothesis Testing Videos: bit.ly/2Ff3J9e
►Linear Regression Concept and with R Videos: bit.ly/2z8fXg1
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Content Creator: Mike Marin (B.Sc., MSc.) Senior Instructor at UBC.
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Thanks for watching! Have fun and remember that statistics is almost as beautiful as a unicorn!
👋🏼 Hi There! In this video we answer these questions: what is the Standard Deviation? What does the standard deviation measures? why do you divide by (n-1) (Degrees of Freedom) and more with examples. If you like to support us, you can Donate (bit.ly/2CWxnP2), Share our Videos, Leave us a Comment and Give us a Like 👍🏼! Either way We Thank You!
LOL. Loved the end voice.
thanks, that's our son...he's starting to contribute to the video production ;)
This video does a good job of explaining degrees of freedom as well!
thanks...it's a bit of a tough one to explain...over the years, ive come up with a few more intuitive explanations for it...but always a challenging one...
I always memorized the formula and never really thought about it, until now.
yeah, unfortunately a lot of the courses i took also focussed on memorization over understanding. we've currently got about 25 of these videos in the editing stage, and another 25+ to get recorded and then edited. they all will focus on the concepts, not the calculations,...so keep your eyes out for those...we're going to roll them out over the summer!
Sir, you are a legend. I enjoy every piece of information you say. The best statistics course on the whole Internet.
Thank you so much.
Thanks, I really appreciate that :)
if you can't explain it simply you didn't actually understand it. You're awesome. You takes simple example to explain complex terminologies . thank you
It has been a year I was wondering why we subtract 1 from n when calculating the sample std. Thanks for this informative video! Amazing delivery!
Breaking down complex things into simpler things(Easy to understand).
you're GREAT.
Thank You very much sir. You helped understand degree of freedom in a simple way
Sir you made statistics very easy for me, very usefull course, Even in paid courses we cannot see such kind of explanation,
you gave me freedom from "degrees of freedom" very well explained. I am so unfortunate i have not met you so far. But i felt so fortunate the moment i saw your videos on stats. Awesome stuff. Marin.
Explaining degrees of freedom while writing mirror image of every character on the glass. Impressive!
thanks :)
You are the best statistician. Thanks a lot.
thanks, appreciate that!
Mike!! Good to see you^^ its been a long time!
Hey Mike! Wonderful description in brief. Now, I feel I can use these stats videos to make my dream come true (jumping into data science).
Hoping to learn a lot of stats to make my foundations strong.... SALUTE
Hope you enjoy them, and learn a lot :)
Very intuitive explanation.
Great teaching and explanation/example of degrees of freedom, variance and SD. thanks!
Omg, everything have made more sense to me now!
You made pretty easy every concept of statistics. Thanks for your effort.
Thankyou so much for the degrees of freedom concept! It was so simple yet so elusive to me till now
thank you sir, your explanations are very simple and has lot of useful information.
thanks a lot very for explaining in easy manner. I tried many videos but u cleared my degree of freedom concept. please upload a video which include most useful terms of statistic for data science
very useful explanation
Yay! Mike finally shows his face :) Thanks for this video Mike
lol, it took a while...now we'll have to try and get Ladan in front of the camera ;)
and Kian too ! :)
Excellent
Thank you Sir
Thank you for this simple and effective explanation!
You’re welcome
Thank you very much for the explanation. As an English learner, I could understand what you expalin and aslo be interested at your video.
great to hear!
You have explained it so clearly, Thank you!!
Thanks for the video. Do you have any video or material on internet which explains this mathematically? As you said , intuitive explanation is easy to grasp and a good starting point, like an analogy. Mathematical explanation gives the complete understanding.
Bessel's correction
You videos are amazin,g thank you so much!
Superb explanation. Thank you so much.
I did not understood why I subtract 1 from n, thanks for clearing this concept.
Thanks so much!
Excellent!
Yep very good indeed thanks Mike
You are just brilliant
Why divide by the degrees of freedom? Dividing by n makes sense because that it how you find an average. Why divide by the degrees of freedom to get an average? I haven't been able to figure that out and no seems to want to explain this on CZcams. They just stop at "the degrees of freedom are n-1" and conclude with that's why n-1.
At 9:45 i understand that x_4 is determined by everything else and the degree of freedom is three, but i dont understand why we still wouldnt use all four to determine the spread. Why is this.
This would suggest that for the case of two numbers we wouldnt divide the sum of the squares by two but by one which seems very unintuitive if we are getting the sd of two values.
Wonderful video. I remember hearing a version of this presentation in my first statistics class back in 1972 or so. I'll encourage my students to watch this after they fail to understand my presentation on the topic. (By the way, can you explain the software/video technique that puts you behind the board?)
lol thanks! as an FYI, we are working on videos like this to fill out most of what is covered in a typical intro stats course, so please feel free to recommend as many as you see fit you your students.
the tech is something called "light board". at UBC we get free access to it through "UBC Studios". many other universities also have a version of this. essentially, it is a sheet of glass that i write on with a set of neon white board markers, and a camera on the other side of the glass. after it is recorded, they flip the image (that's what it looks like I'm left handed...im actually right handed). if you search "light board" on CZcams you can find some videos that show it. you can actually build one for pretty low cost (if you are handy). fortunately, we get access to one that has been built, and has technicians to handle all of the tech for us...
Thanks. I looked up the developer's website and it really does look like something that could be created for a reasonable cost. I'll be looking for additional videos as they are produced, as my students (especially in online sections) can use all the help they can get. I make use of many of your R videos and have found them among the best for basic concepts is R.
Great production!
Excellent
Thank you for all the videos! Do you have please tutorial about how plotting standard deviation with R studio?
Thank for the video. it is so informative and useful.
Thanks
We talk about degrees of freedom when we use t, F, Chi or other distributions while testing hypotheses, but we do not not talk about them when using z test. Why? And are you aware of any article that answers or discusses this topic?
I have a question: why did you not put the number on module instead of square the numbers? The calculus would be much easier to solve, also It could have worked better if the problem lays on opposite signs canceling each other out.
if he's on the other side of the glass is he writing everything laterally inverted so we can read them normally?
lol, no what happens is that the image is "mirrored" afterwards, so that things flip and are visible the right way. im actually right handed, but in the videos i appear left handed because the image has bene mirrored :)
It's good actually it's good 😊
Awesome
sum of all the deviations / no. of deviations = average deviation (from the mean)❤️👍
Thank you so much Mike! and tell that lil boy i love stat too...sweetu
#edited
i wiil...that's our son...he wanted to contribute to our videos too ;)
you are great!
beautiful
great
okay, so I understand losing a degree of freedom, and that makes sense for multiple values. But how do you explain one variable. The deviation, any type, should be zero, since it is itself the mean. However, when using n-1, you'd get zero, which implies that the standard deviation does not exist for one variable, is that correct?
yeah, that's basically it. with a n=1, that observation is your estimate of the mean, and you dont have any data/observations left to estimate the SD with....your df become 0...you have no degrees of freedom left to estimate the SD with
@3.29 Why would we want to plot x vs abs(x) here in the scenario?
This explanation was meant to remind that working with absolute values is not a smooth mathematical function, while working with “squares” is a smooth mathematical function with nicer mathematical properties.
Really, just wanted to make the point that using squares is a (reasonable) choice, but not the only option...and to explain why the SD doesn’t use absolute values instead
Is he writing backwards or there is a program for this?
my thoughts exactly, it seems so.
It deosnt make sense to me. How come one knows the mean 80 without knowing x4? x1 x2 x3 and x4 all has to be known to know their mean. I dont get this.
Yes it is great to see your face. :-)
thanks, i took a while before finally getting in front of the camera :)
07:20
The videos in this playlist are not in order. If you could put them in order, it will be a great help.
Even I find videos are not organised in a fashion.
this explains the degrees of freedom well ... but it didn't explain why we need to divide by DOF instead of n?
Okay, but the real question is how is this guy writing backward?