9 years later students are still being saved by this. Super grateful!
@toyinamunigun2043
3 жыл бұрын
I swear
@niizumashiiori6402
3 жыл бұрын
it's true...
@dryrain2
2 жыл бұрын
Make it 10 years later!
@mylesarsenault9016
2 жыл бұрын
@@dryrain2 make it 11
@OryxTheDragon
2 жыл бұрын
12 years now.
@andrewtataj497
11 жыл бұрын
dude, your math videos are the best ones I've found. My prof is awful, I'd be lost without these.
@MutantNinjaFly
13 жыл бұрын
My stats teacher just throws a bunch of formulae on the board, and then when you have to do stuff I have no idea where the distributions come from or what they are used for, how to use them, or what they mean.
@salilbane2675
4 жыл бұрын
Lol
@meno2739
3 жыл бұрын
Holy crap You wrote this message 9 years ago when and I have to say, things don't change...
@sanketnawale1938
3 жыл бұрын
I am curious what are you doing now after 9 years.!
@Ryan라이언
3 жыл бұрын
I can't agree more ROFL
@sisca8536
2 жыл бұрын
this is exactly what my teacher does, things dont really change even after 11 years 🤷🏻♀️
@MASTER3XPL0D3R7
12 жыл бұрын
Thank you so much. My university lecturers aren't great, and I just can't learn maths from a textbook. It helps so much that you have explained it in such a simple, clear way.
@ShivamRaj004
9 ай бұрын
How's your maths now?
@camadamsuk
11 жыл бұрын
I love your videos Sal, the one concept I still dont understand is degrees of freedom. i understand what they do but not what they are. I think you explained them at one point but i couldnt find the video looking back through the playlist. maybe dedicating a video to df would be helpful for other statistic students as well. thanks!!!
@lamvo21
2 жыл бұрын
12 years later and still useful!! Thank you so much
@akshaykulkarni3208
Ай бұрын
Khan acadamy to the rescue.. Love it
@mitchjohnson4714
7 жыл бұрын
This is such a great video. It's amazing how much great information is conveyed in such a simple and succinct way.
@yiklongtay6029
6 жыл бұрын
I am too stupid for this.
@glaswasser
4 жыл бұрын
my thoughts everytime I study something math-related lol
@chandakabwe5994
9 ай бұрын
😂😂😂😂😂😂😂 really
@sumiatheangel9397
8 жыл бұрын
This guy's classroom probably has more A's than an Energizer factory. ~Reus Vult Ave Sumia, Pegasus Breeder and Root Beer Connoisseur
@Jikrin
3 жыл бұрын
Unlikely, for most colleges, there is an implied rule that most students will not get an A.
@Newbiefly7698
3 жыл бұрын
At 04:45 please explain how a probability distribution sample has a probability of greater than 1 in the chi square curve for k=1?
@norwayte
14 жыл бұрын
Could you record a video about degrees of freedom?
@mpalin11
11 жыл бұрын
A very nice video, I have a statistics course now, this was really helpful! Thank you!
@noueruz-zaman7894
7 жыл бұрын
lol its called ki-square ..and I have been calling it Chi-square (like chili)
@lyannamormont298
6 жыл бұрын
Same here bruh😂😂😂..you can't imagine the embarassment i felt after finding out
@editsjag6160
5 жыл бұрын
Actually it should be pronounce chee, not ki. The letter is chi, it is greek and that is how it is correctly pronounced. Same with pi, it should be pronounced pee
@glaswasser
4 жыл бұрын
our teacher usually says "guy square" :D
@tonimatasnim
13 жыл бұрын
I love this guy.
@vasishtapolisetty639
Жыл бұрын
Coming back after 10 years. Thanks Sal!
@aldezmail
12 жыл бұрын
His handwriting is great with the mouse, he must be awesome at shooters, HEADSHOT HEADSHOT
@vivekmittal7893
6 жыл бұрын
aldezmail he most likely uses a digital pen.
@cc32001
5 жыл бұрын
@@vivekmittal7893 Probably right, but I trip out the whole time I'm watching him thinking what if he was writing with a mouse. The thought distracts me the whole time.
@diegoguzman6004
11 жыл бұрын
You are a magician man, thank you!
@superpeaceloveunity
5 жыл бұрын
I'm lost right from the beginning. I'm using the Pearson book for stats class and I think it takes a completely different approach to the chi-distribution. It isn't close to being clear to me yet.
@hassanxami6527
Жыл бұрын
Still watching it in 2023. He helped everyone
@蒋俊杰-x6v
6 ай бұрын
I’m from 2024
@Catalonia
13 жыл бұрын
I'm a bit lost.. is there a preliminary video to this? I don't know the language.
@mistyshawn4066
8 жыл бұрын
i can pass my exams because of you..thank you so much!
@pmactwins2
6 жыл бұрын
When the probability is .3, that gives us the value at 2.41 … but aren’t we looking for values greater than 2.41? I think I’m misunderstanding. I would think the answer would be .3 if the question asked P(Q2 ≥ 2.41) … but since we’re strictly looking for values greater than 2.41 I would think we would move up one box … can anyone explain?
@kowtharhassan882
10 ай бұрын
The key in teaching stats is to use examples and not just terms so instead of saying variable X it would be better if u did indeed use a variable like weight, height, or anything else so we can follow
@DumboSanchez
11 жыл бұрын
I'd be lost without these videos man many thanks!!
@StanleyMT
12 жыл бұрын
Im not sure I understood much from this explanation. I would have prefered a more practical application. Could you indicate if you have another video. Also as it relates to the degree of freedom I was a little confused as I thought it was n-1 but you seem to suggest its = to n
@sgdrifter
7 жыл бұрын
it will be better if the origin of these terms (motivation of creation of these terms) are explained in advance of these tutorials. anyway, these tutorials are great :)
@petrhorak931
11 жыл бұрын
Khan is my hero.
@hongkyulee9724
2 жыл бұрын
Thank you for the nice video :D This video is really helpful!!
@navedkhan4057
2 жыл бұрын
Great video!!! just wanted to understand why do we square X1 and X2?
@ayush612
6 жыл бұрын
Awesome Explanation Sir!!! Thanks for the valuable knowledge !
@eseemuraye1230
5 жыл бұрын
I am currently in my Statistics class, waiting for my Professor to finish his lecture on Chi-test (which I don't understand by the way and feeling dizzy) so I can come back here to get the real lecture
@2pizen
11 жыл бұрын
really great videos!! keep up the good work!
@phamdung3884
Жыл бұрын
Thank you so much! This is THE video that really taught me the concept of Chi squared distribution.
@noortjeburg4504
7 жыл бұрын
Thanks! Never had a class for this subject but now I understand it all!
@feel2founded
6 жыл бұрын
Great video! Actually all your videos are really helpful and make things understandable and even intuitive in a way :) Thank you!
@Josiah_Cornett
5 жыл бұрын
So, I'm studying for Actuarial Exam P and in a sample exam i'm taking, there is a time when I have to just somehow know that the sum of two squared standard normal random variables is exponentially distributed. Well, more precisely, I"m asked to find the moment generating function of (X^2 + Y^2) / 2 where X and Y are distributed N(0, 1), but in the solution they just throw out there that "Obviously" X^2 + Y^2 is exponentially distributed with hazard rate 0.5 and mean 2. I just don't know how they know that. Wouldn't it be easier to use that this would be Chi-squared?
@eXcelMathS
5 жыл бұрын
you can prove by joint pdf of X and Y, and switch to polar coordinates that sum of squared standard normal random variable is exponential distributed. It all depends on how the questions are phrased though
@Joske369
12 жыл бұрын
thank you, that helped alot for my exams
@tvvt005
19 күн бұрын
6:36 the various standard normal variates come from different normal variates right? Cos otherwise they would be the same right?
@Trackman2007
12 жыл бұрын
So standard normal distribution is normal distribution's z-scores distribution?
@tebellomokgomole772
6 жыл бұрын
I can't believe this. How come I understand, all this time I only understand now. But how. Thanks Khan
@sherlockholmes882
5 жыл бұрын
Thanks for visually explaining what this distribution means!
@jonasherman9195
2 жыл бұрын
I am pretty new to Statistics, what is the use of a chi-square distribution, based on what I have seen a question could be: What is the chance that it is under this value or is this chi-square distributed.
@HL-iw1du
3 жыл бұрын
Khan is so smart.
@Xercaas
12 жыл бұрын
Excellent, very instructive
@maxwellgordon3739
5 ай бұрын
Maseno University Kenya super supportive
@nicolechong620
8 жыл бұрын
it's useful, thanks so much.
@joshuafancher3111
6 жыл бұрын
Great explanation!
@VelMurugan-me3xh
6 жыл бұрын
Thanks for this video
@mrak8948
3 жыл бұрын
Thank you
@mar8014
11 жыл бұрын
Sal's VOICE gives me CONFIDENCE.
@themagniranthine
2 жыл бұрын
Why do chi-squared distribution and chi-squared test have different formulas? Please answer, I'm going to have a presentation tomorrow 🙏🏿
@lagoscristiam
6 жыл бұрын
Thanks for the videos, what software is he using? Excel?
@memski9565
4 жыл бұрын
My professor is all good...but I'm here since I was dumb enough not to listen in class
@sharonchetia54
4 жыл бұрын
I am really confused with the degree of freedom . I know that formula is : Number of independent variables- Number of constraints. Is degree of freedom 1 when we consider 1 variable because it is an independent variable and we are not doing analysis involving a constraint?
@sanjeevghimire9459
8 жыл бұрын
Good
@marcoskano4437
6 ай бұрын
13 years later and here I am, finally my turn to watch this for an exam 🎉
@marcwittkowski5146
2 күн бұрын
I have absolutely no concept of what you could possibly mean by degrees of freedom.
@DK-ek9qf
3 жыл бұрын
Thanks a lot
@K1312-s8d
6 жыл бұрын
For degrees of freedom, why are we not applying the rule of n-1. E.g. If you take a sample of 1, you are saying the df is 1 but should it not be (1-1) 0?
@eXcelMathS
5 жыл бұрын
the rule of n-1 is applied supposingly when X ~ N(mu, sigma^2) where mu is unknown and you use the sample mean to estimate. Because mu is being estimated it takes away 1 degree of freedom when doing chi square test. By the way in this case X has to be converted to standard normal first because it is not.
@JelinekFS
8 жыл бұрын
Actually this introduction vid seems to be the only of your chi-square vids I´m having a hard time to understand haha. I guess I shouldn´t have skipped the basics.
@pricillajeyapaul
3 жыл бұрын
Does chi-squared distribution formula is E(X)=k, V(X)=2k.? Correct me if this wrong.
@nO_d3N1AL
12 жыл бұрын
great stuff as always
@jessstuart7495
7 жыл бұрын
You forgot to normalize the new chi-squared distributions. You need to make sure the multiple integral ("volume") under the multivariate probability distribution is equal to 1.
@Nickiller6969
13 жыл бұрын
ur awesome mate
@Tweeteketje
10 жыл бұрын
You're the best!
@sjsawyer
13 жыл бұрын
Damn it.. my x's looked like chi's to begin with!
@Mandee1310
10 жыл бұрын
how do you know the degrees of freedom?
@hseager
10 жыл бұрын
number of parameters you are estimating
@mitchellkoenig1540
7 жыл бұрын
it should be n-1 and not just n as he makes it appear in this video
@eXcelMathS
5 жыл бұрын
it depends on number of X you have, and number of unknowns you are estimating.
@Joske369
12 жыл бұрын
ur a hero
@xojessie75xo
5 жыл бұрын
I am currently taking a biology class, and one our EXTREEEEMELY DIFFICULT assignments is 'Chi Square Test and Corn Genetics Lab'.. I am sooooooo lost!!! I have absolutely NOOOOOOOOOO idea what to do! PLEASE HELP!!!!!!!!!!!!
@hikarisai7755
11 ай бұрын
What's the degree of freedom?
@julianbenegas512
5 жыл бұрын
How is sigma squared = sigma??? I thought (and been taught always) that standard deviation (sigma) was the square root of the variance (sigma squared)
@natrajtarnalli5903
6 жыл бұрын
Can you explain what exactly X and Q are in real experiment.. may be with some example!
@eXcelMathS
5 жыл бұрын
X is just a random variable sampled from N ~ (0,1), while Q is X^2 in which X is randomly sampled standard normal random variable
@yasminfatima5948
4 жыл бұрын
@@eXcelMathS Why the degree for freedom from first sample distribution is one and so on?
@peuchi1602
7 жыл бұрын
How does this distribution approach standard normal distribution (mean = 0) as df increases if the mean is increasing? Isn't it just approaching a normal distribution (not standard normal)?
@KMED-gc7gv
7 жыл бұрын
yes, it won't be standard.
@eXcelMathS
5 жыл бұрын
when n tends to infinity, by central limit theorem, it approaches standard normal.
@16jrsoccer
14 жыл бұрын
You're the bessst
@johnmandrake8829
3 жыл бұрын
Not all heroes wear capes
@workh4rd
11 жыл бұрын
yeah, i thought he was writing with a mouse too. but from the writing style, i think the mouse is very likely to be made in pen shaped.
@kvamshi4561
5 жыл бұрын
😂😂
@medielijah
4 жыл бұрын
why is it that P of Q2 greater than 2,41 and not SMALLER than 2,41??? I do not get how he got to that conclusion
@qjim16
4 жыл бұрын
Try to draw one of those graphs. Khan can't do that.
@lifewithdylan
6 жыл бұрын
amen
@Mike_elGreco
2 жыл бұрын
When I first see the of chi-square in English I thought was something chinese pphrase
@bellybooma
5 жыл бұрын
I love Sal
@d.a.d3513
2 жыл бұрын
After 11 year
@junmingzheng7456
5 жыл бұрын
so that's where the square coming from??????
@tsunningwah3471
2 ай бұрын
sdks
@johncharles3907
6 жыл бұрын
so wat the hell is it used for?
@choice_architect
7 жыл бұрын
Although derived from one another, standard deviation isn't the same as variance. It's true that variance is the measure of spread of the data around the mean, but it by itself can't be interpreted. If we take the square root of the variance, we obtain the standard deviation, which is what we see when we look at spread around the mean in the normal distribution. In the case of N(0, 1), the population mean is zero and its variance is one; the square root of one is one, so our standard deviation becomes one. If we have N (0, 2), however, then we have a mean of zero and a standard deviation of ~1.41.
@mitchjohnson4714
7 жыл бұрын
I think he was just talking about when the SD is 1.
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