Central limit theorem | Inferential statistics | Probability and Statistics | Khan Academy

Поділитися
Вставка
  • Опубліковано 25 січ 2010
  • Courses on Khan Academy are always 100% free. Start practicing-and saving your progress-now: www.khanacademy.org/math/ap-s...
    Introduction to the central limit theorem and the sampling distribution of the mean
    Watch the next lesson: www.khanacademy.org/math/prob...
    Missed the previous lesson?
    www.khanacademy.org/math/prob...
    Probability and statistics on Khan Academy: We dare you to go through a day in which you never consider or use probability. Did you check the weather forecast? Busted! Did you decide to go through the drive through lane vs walk in? Busted again! We are constantly creating hypotheses, making predictions, testing, and analyzing. Our lives are full of probabilities! Statistics is related to probability because much of the data we use when determining probable outcomes comes from our understanding of statistics. In these tutorials, we will cover a range of topics, some which include: independent events, dependent probability, combinatorics, hypothesis testing, descriptive statistics, random variables, probability distributions, regression, and inferential statistics. So buckle up and hop on for a wild ride. We bet you're going to be challenged AND love it!
    About Khan Academy: Khan Academy offers practice exercises, instructional videos, and a personalized learning dashboard that empower learners to study at their own pace in and outside of the classroom. We tackle math, science, computer programming, history, art history, economics, and more. Our math missions guide learners from kindergarten to calculus using state-of-the-art, adaptive technology that identifies strengths and learning gaps. We've also partnered with institutions like NASA, The Museum of Modern Art, The California Academy of Sciences, and MIT to offer specialized content.
    For free. For everyone. Forever. #YouCanLearnAnything
    Subscribe to KhanAcademy’s Probability and Statistics channel:
    / @khanacademyprobabilit...
    Subscribe to KhanAcademy: ua-cam.com/users/subscription_...

КОМЕНТАРІ • 336

  • @adamromero
    @adamromero 11 років тому +468

    Why can't teachers explain things this clearly, why do they have to act all scholarly?

    • @deepakrp
      @deepakrp 4 роки тому +87

      because they don't understand it either!

    • @alenjose3903
      @alenjose3903 3 роки тому

      did u watch the next few lessons?

    • @yuningliu6300
      @yuningliu6300 3 роки тому +5

      because they are scholars, not pragmatist, like you !

    • @glennhenshaw7474
      @glennhenshaw7474 3 роки тому +4

      Well I think what's mostly going on is that there are different levels of understanding for a topic. Sometimes, if the explanation is not clear it's because the instructor is making room for some of the subtleties down the line. For example, imagine how confusing Newtonian mechanics would be if instructors always fixed the tiny error due to relativity. Or, like someone said below--maybe they don't have a clear understanding yet.

    • @blakeelzinga1168
      @blakeelzinga1168 3 роки тому +15

      a true mastery means that one can teach it simply and clearly

  • @gopikarajanikanth4482
    @gopikarajanikanth4482 9 років тому +323

    Honestly, this almost 10 minute video helped me understand something we were learning in class for like 2 weeks! Thank you so much!

    • @johnanderson8765
      @johnanderson8765 4 роки тому +4

      that two weeks of study is the reason you can enjoy this clip so much.

    • @aniruddha4672
      @aniruddha4672 4 роки тому +8

      @crni195 Like a true engineer you had to point out that you are one lol

    • @natureloving785
      @natureloving785 2 роки тому

      Superb Khan sir, am very pleased to study statistics as I watched your 10 minutes videos

    • @shakuntalakamade
      @shakuntalakamade Рік тому

      are you alive ?

  • @matthewwroblewski8752
    @matthewwroblewski8752 8 років тому +315

    Very, very cool stuff. Also, you're obviously a smart guy, Sal. But at the same time, you're incredibly accommodating to us students. Thank you for your sincerity and empathy, sir.

  • @mimireyes04
    @mimireyes04 6 років тому +236

    cramming for my stats exam tomorrow

    • @EmberArcher
      @EmberArcher 5 років тому +13

      Cramming for my stats final today

    • @carterwest9504
      @carterwest9504 4 роки тому +21

      same except in 20 minutes

    • @swatibiswas6796
      @swatibiswas6796 4 роки тому +1

      Me rn

    • @CrunchyDark
      @CrunchyDark 4 роки тому +3

      Not cramming. :P trying to learn it as much as possible.

    • @thesevenkg
      @thesevenkg 3 роки тому +5

      @@CrunchyDark big flex

  • @i6mi6
    @i6mi6 7 років тому +656

    Drinking game: drink whenever you hear the word "sample"

    • @TeeNanners
      @TeeNanners 6 років тому +13

      i6mi6 I might need to play that game to get over my probability score... D;

    • @rogersyversen3633
      @rogersyversen3633 6 років тому +1

      no

    • @nellyaviles9342
      @nellyaviles9342 6 років тому +9

      lets just kill braincells before the exam..

    • @samdavepollard
      @samdavepollard 6 років тому +14

      Are you intoxicating that I'm insinuated?

    • @skyepaul261
      @skyepaul261 6 років тому +10

      I'm trying to study here shhh

  • @meganmaloney192
    @meganmaloney192 8 років тому +44

    These videos have been tremendously helpful! Thank you SO MUCH for making them! The concepts make so much more sense when I can see them being worked out.

  • @esmeralda4884
    @esmeralda4884 8 років тому +54

    You explain this better than a textbook. You are a great!

  • @SuperYtc1
    @SuperYtc1 7 років тому +78

    Fantastic explanation. A shame that most teachers are not educated enough to be able to understand and explain things like this to their students.

    • @sophiefeng2740
      @sophiefeng2740 5 років тому +2

      so true

    • @mrknarf4438
      @mrknarf4438 4 роки тому +18

      ...and when they are educated, they start believing it's super obvious so they just tell you what it is without examples and in depth explanations and jump straight to the following topic, expecting you to have not only understood but also interiorized the concept.

    • @Saiphel
      @Saiphel 4 роки тому +7

      @@mrknarf4438 This so much. I love when they have 200 students in front of them and when the teacher asks for an answer to a question and nobody answer it's everyone else's fault. They never think maybe it's their fault they suck at teaching. Sal is amazing, I only wish topics were more in depth.

  • @jasminespence6452
    @jasminespence6452 3 роки тому +30

    Dear Sal. I always skip all my calculus and statistics lectures and come straight to your videos. This has been the secret to my success in university. Thank you!

  • @BboyFadi
    @BboyFadi 8 років тому +17

    you are amazing , thank you , not only for this video , but for all your videos that i have been using for 3 years :)

  • @Bella_Noches_
    @Bella_Noches_ 2 роки тому +2

    This video summed up in almost 10 minutes what I have been trying to understand in my textbook for the past week. Good stuff...thank you!

  • @stelun56
    @stelun56 2 роки тому +5

    I have been a mathematician all my life. I dropped out after middle school but started to get bored, so I bought some mathematics books with the answers at the back and used them to self-study for university entrance in the UK. That was 50 years ago before I graduated with scholarships for Oxbridge after gaining a double first-class in pure mathematics and theoretical computing. With hindsight, I feel your videos would have been really useful for statistics which I dropped for pure mathematics, applied mathematics, and physics. You are always highly recommended to all my tutees struggling with their education during this pandemic. Excellent material!

  • @hexiaohuang857
    @hexiaohuang857 4 роки тому +2

    Thank you! Thank you so much! Thank you very much! I have been in Intro to Econometric class for 2 months already. I feel I understand more from your video for 10 minutes than in class for 2 months

  • @Wooktent
    @Wooktent 4 роки тому

    I was given 3 20 minute videos on this subject and I didn't understand a thing they were trying to tell me, but I watch one 10 minute video from you here, and I completely understand this now. Thank you so much, KA.

  • @hou950
    @hou950 4 роки тому +6

    You are helping me get through my graduate level quantitative analysis classes. Thank you so much ! =)

  • @serachrysanthemum9687
    @serachrysanthemum9687 7 років тому +2

    Heck yeah, this is a great motivating video... gives an outline of the idea and why it's so cool and important!

  • @bluesky-mi2sx
    @bluesky-mi2sx 4 роки тому +3

    This video was posted 10 Years ago and still so useful!
    Such a crazy thing

  • @RachelLovelace
    @RachelLovelace Рік тому +8

    So cool. I took Stats 101 about nine years ago, and these videos were there for me. I'm back in grad school now, and you're videos are helping me with Applied Stats once again. You rock!

    • @soumyaranjandas7394
      @soumyaranjandas7394 8 місяців тому

      Can u explain me in somewhere.... actually I didn't get what is related to central limit theorem. Is it Sample size or no. Of samples from which we calculate mean.

  • @kwsatl6066
    @kwsatl6066 9 років тому +1

    went to lecture today and read the chapter and was clueless. I watched the first 7 minutes of this and the concept is crystal clear!!

  • @Abubakar-ht5ee
    @Abubakar-ht5ee 5 років тому +2

    you guys are shaping history. thank you.

  • @obinnadaniel2001
    @obinnadaniel2001 7 років тому +2

    I mean this is brilliant! Got me thinking and understanding deeply.

  • @usharagunath23448
    @usharagunath23448 5 років тому +1

    may god bless you Sal!!
    You are my guru
    you are the voice in my head as i solve math

  • @ytkv
    @ytkv 8 років тому +2

    Best explanation out there. Thanks, Sal!

  • @18gshock
    @18gshock 12 років тому +1

    Nothing much to say how good you are, the video tells it all, keep up the good job!!!

  • @SandroAndrade
    @SandroAndrade 12 років тому

    I'd like to really thank you for your videos. All of them with great didatics and only now made some aspects of statistics very clear for me :)

  • @aprilhicks3474
    @aprilhicks3474 4 роки тому

    You just made life so much more interesting. Love you Sal! Will donate soon.

  • @8dannygirl
    @8dannygirl 11 років тому

    You just saved my life brv.....you explained in 9 minutes and 49 seconds ,what ive been trying to understand for the last 2 hours.

  • @TheSevenofMine
    @TheSevenofMine 9 років тому +5

    I like it that it's called Khan Academy. KHAAAAAAN!!

  • @diencai1812
    @diencai1812 4 роки тому

    Thank you for your clear explanation. You are a world class educator!

  • @That1KoreanGuy
    @That1KoreanGuy 11 років тому +2

    This channel is a life saver!

  • @joed9229
    @joed9229 9 років тому +2

    khan is awesome ! Im in this course that could not explain this well. I need to know the principle and Khan blew it out of the water ! I know the principle and the APPLICATION ! sweet

  • @LeahInTheRye
    @LeahInTheRye 10 років тому

    Thanks! Got a test that includes this section next week and it had me stumped

  • @hennageorge3259
    @hennageorge3259 7 років тому +7

    If x = 1,3,4 or 6 and the sample size is 4, there would be 4*4*4*4 possibilities i.e. 4^4 possibilities =a maximum of 256 possible outcomes so by taking 10,000 samples you will be repeating each 1 about 40 times.

    • @noahschuler6388
      @noahschuler6388 5 років тому

      Henna George yes, and if you take an infinite amount of samples, the distribution of the sample means will show the probability of getting each sample.

  • @lorassa727
    @lorassa727 11 років тому

    THANK YOU!! Your videos are amazing, such an amazing and intelligent man!

  • @thuuyenphamnguyen8899
    @thuuyenphamnguyen8899 4 роки тому

    my teacher just mentioned the central limit theorem and did not explain it (in 1 week!) :D and I just spent 10 mins to watch this clip to understand what he tried to explain in 1 week (and no one understand) :D thank you so much!

  • @pratibhas2468
    @pratibhas2468 Рік тому +1

    It's been 13 years since upload and people like me are still using these videos... Great explanation!

  • @rideshareescapades4281
    @rideshareescapades4281 11 років тому

    I love you man
    it's a lot of fun learning this stuff.
    Thanks a lot

  • @kristennwang
    @kristennwang 2 роки тому

    I never took a stats class in high school or college and the bootcamp class I am currently taking does not do a good job at explaining this theorem. So who do I turn to? Sal! I grew up with you and you are still helping me learn even in my near thirties. Thank you!!!!

  • @davidmbeckmann
    @davidmbeckmann 9 років тому +1

    Very instructive video!

  • @mostinho7
    @mostinho7 4 роки тому +1

    Done thanks
    4:30 looking at the SAMPLE MEANS (taking a sample of n measurements, then averaging those n measurements is the sample mean), doing this for x samples of n measurements we have x sample means
    The distribution of these sample means tend towards a normal distribution as we take more samples. Also as the sample size the number of measurements in each sample increases, the sample means distribution approximates normal even more

  • @rodrigomorgado5524
    @rodrigomorgado5524 4 роки тому +1

    A good way to explain CLT. From an unknown discrete distribution to converge to a normal distribution.

  • @winterfell14
    @winterfell14 11 років тому +3

    Oh man, that is SO logical!

  • @lorrainepinon
    @lorrainepinon 11 років тому

    helped me to pass my statistic class. thank you!

  • @misterwessels
    @misterwessels 13 років тому

    Thank you very much for this very clear explanation!

  • @jamesrobsonza7752
    @jamesrobsonza7752 4 роки тому

    Much better explanation than my textbook, thank you so much

  • @MayankMehta-pr9eg
    @MayankMehta-pr9eg 3 місяці тому

    Once again Khan Academy saved me from the state of I am not able to understand to how easy is this stuff. Thanks

  • @ChitimachanPanda
    @ChitimachanPanda 11 років тому +2

    "1" is one element of the sample, so is another "1", as well as "3" and "6", therefore there are 4 total elements that comprise the whole sample, thus the sample size, n, is equal to 4. It's 4 in this case because that is the sample size this person decided to use for his test. Higher sample sizes usually lead to more accurate tests.
    If I say "What is the sample size of all possible outcomes on rolling a die?", there would be 1, 2, 3, 4, 5 and 6, meaning n=6.

  • @iraklismoutidis204
    @iraklismoutidis204 6 років тому

    Thank you for this explanation. I would like to ask you a question. If we got a distribution (probably heavy tailed) and take many samples with different size (for example the first sample will have 30 samples, the second 40, the third 34, the fourth 51 and so on) will then the distribution of those samples be normal?

  • @floh223
    @floh223 5 років тому

    The video is simply beyond cool. Thank you so much sir.

  • @pritivalecha3147
    @pritivalecha3147 2 роки тому

    thanksss, i loved your video, i was looking to prove CLT and it clarified niceee

  • @user-mn1od5il7w
    @user-mn1od5il7w 6 років тому

    Your video is easy to understand. Thank you^^

  • @yitianxiao6650
    @yitianxiao6650 3 місяці тому

    thanks. This is way more straight forward than the aihl textbook

  • @choppertalk8291
    @choppertalk8291 11 років тому +1

    Very clear. Thank you

  • @SuperTurkeyKing
    @SuperTurkeyKing 11 років тому

    OMG!!!u r much better then my lecturer!!! He talks like a computer n I can just keep copying the solution of the examples during the class!!!!
    I understand much better becoz of u!!!!!!thx a lot!!!!!!!!!!!

  • @karafofubuntu
    @karafofubuntu 10 років тому

    Thank you so much for a clear explanation.

  • @ShroukAbdulshafy
    @ShroukAbdulshafy Рік тому

    Very helpful! thank you so much, Sir!

  • @LYLxd
    @LYLxd 12 років тому +3

    YOU ARE SO AMAZING. PLEASE KEEP DOING WHAT YOU'RE DOING.
    I need to pass my exams...

  • @shahronak47
    @shahronak47 9 років тому

    Great explanation!!

  • @AbirChoudhury101
    @AbirChoudhury101 7 років тому

    Thanks for the explanation!

  • @ayonrab
    @ayonrab 13 років тому

    God bless you ! I got this after 10 years...

  • @nasratullah5596
    @nasratullah5596 5 років тому +2

    This is extremely well explained ! Thank you teacher.

  • @shareef3743
    @shareef3743 8 років тому +5

    damn this is actually really cool

  • @goktugguvercin8069
    @goktugguvercin8069 5 років тому +1

    You can use the word "observations" for the elements in a sample.

  • @J0EH3AD
    @J0EH3AD 13 років тому

    Thank you for very nice and instructive Probability series. I would like to see mathematical analysis of random walks - will you create it?

  • @guptaaniket274ag
    @guptaaniket274ag 2 роки тому

    Thankyu so so much!!!!!

  • @matevarga1401
    @matevarga1401 4 роки тому +1

    This was a very useful video. Thank you so much. Clear and interesting explanation. Although the "peak" of the normal distribution should be around 3.5 in your example, not 2.75. Since that's the mean. Right?

  • @samadhashmi
    @samadhashmi 8 років тому +1

    I love statistics!

  • @EclipZeMuzik
    @EclipZeMuzik 6 років тому

    awesome video!!

  • @jordantan5023
    @jordantan5023 2 роки тому

    Very Good example ... I was having problems with figuring out how the individual mean element was obtained...

  • @GirlGirlicious
    @GirlGirlicious 7 років тому

    You, sir, are The Real MVP!

  • @lyndsays1373
    @lyndsays1373 5 років тому +19

    who's out here cramming for the ap stat exam thursday

  • @SaikatChakrabarti
    @SaikatChakrabarti 13 років тому

    great xplanations sir...thanks so much...

  • @quazinuzhat1515
    @quazinuzhat1515 8 років тому

    you nailed it. thanx a lot

  • @WilliamJSSequeira
    @WilliamJSSequeira 7 років тому

    Jeez, thanks for driving it home! You need to get with a publisher and go wide, you explain in the most basic, and common fundamental way for easy learning.

  • @richaunfacey5447
    @richaunfacey5447 2 місяці тому

    You have a great channel. I am in a master's degree program, and I still use your site.

  • @chaitanyatuckley4666
    @chaitanyatuckley4666 5 років тому

    Beautiful. Made my day.

  • @chopper84a
    @chopper84a 11 років тому +4

    I heard about the elegance of math: think I just got it!

  • @rachitadehury2829
    @rachitadehury2829 8 років тому

    Thank u so very much u helped me a lot

  • @aj-kl7de
    @aj-kl7de 4 роки тому +1

    Thanks Sal !

  • @kushagra452
    @kushagra452 5 років тому

    As the sample size (i.e "n") increases the sample distribution starts looking more and more like the normal distribution. Does it have to do with also the number of samples taken? If I were to take 10000 or 100 sample of the same sample size (n) then would both have the normal distribution? Thanks!

  • @rjeption
    @rjeption Рік тому

    Khan is getting me through college

  • @vishnuvardhan2608
    @vishnuvardhan2608 8 років тому +5

    Sal.... Your my rockstar!

    • @versus13
      @versus13 7 років тому +2

      Your welcome

  • @quinnculver
    @quinnculver 11 років тому

    Very nice explanation. Hats off.

  • @lovelivelife8950
    @lovelivelife8950 8 років тому

    THANK YOU!!!

  • @Zurh1994
    @Zurh1994 11 років тому +3

    Central limit theorem = mind blown

  • @Mlledalia91
    @Mlledalia91 12 років тому

    thank u, so helpfull!

  • @Hunsruck
    @Hunsruck 13 років тому

    Thanks so much !

  • @999tktktktk
    @999tktktktk 5 років тому

    it's really helpful

  • @QweenThrisa
    @QweenThrisa 10 років тому

    It is good to know that your brain malfunctions from time to time, too lol Thanks for the great videos!!!

  • @ekleanthony7997
    @ekleanthony7997 3 роки тому

    great work..

  • @HeyImRod
    @HeyImRod 6 років тому

    Fantastic!

  • @ZbladeVX
    @ZbladeVX 9 років тому

    great vid!

  • @amolbuch8713
    @amolbuch8713 9 років тому

    You are just awesome..!

  • @tilakchanddhital137
    @tilakchanddhital137 8 років тому

    U r helping me a lot :D

  • @jasminnperez
    @jasminnperez 4 роки тому

    thank you!

  • @Lunaizle
    @Lunaizle 12 років тому

    this man khan do anything

  • @mracuraon18s
    @mracuraon18s 12 років тому

    The U-looking symbol you're talking about is the greek letter μ or Mu. It represents the mean. In this video, he used an x-bar (just an x with a bar above) to represent the mean because it is was specifically for a SAMPLE. In other words, you use μ for a population mean and use x-bar for a sample population.

  • @nazifataha8868
    @nazifataha8868 3 роки тому

    It's sad how many people commented here saying that their teacher could not explain it. It seems most teachers are not good at their jobs. Where in the world would we be if we didn't have contents like Khan Academy?? Thanks to the internet. Thanks to people like Sal

  • @meghalbhansali5820
    @meghalbhansali5820 2 роки тому

    This was beautiful

  • @lllBOLTlll
    @lllBOLTlll 12 років тому

    i've figured him out... He went to a good school and learned this beginner subjects and mastered them because of good teachers, and then he words it into a 10 min video and impresses all of us...