Range, variance and standard deviation as measures of dispersion | Khan Academy

Поделиться
HTML-код
  • Опубликовано: 18 апр 2010
  • Courses on Khan Academy are always 100% free. Start practicing-and saving your progress-now: www.khanacademy.org/math/stat...
    Practice this lesson yourself on KhanAcademy.org right now:
    www.khanacademy.org/math/prob...
    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: ruclips.net/user/subscription_...

Комментарии • 671

  • @zinaalabdaly6848
    @zinaalabdaly6848 3 года назад +509

    And here i am, 10 years after this was posted, learning more here in 12 min than my course in an hour
    Thank u from the heart of mine, khan academy !

    • @vincentdrew2194
      @vincentdrew2194 3 года назад +8

      I played this at 2x speed to learn it in 6 min

    • @owenpatenaude1072
      @owenpatenaude1072 2 года назад +2

      Same lo

    • @I_unar
      @I_unar 2 года назад +6

      @@vincentdrew2194 That’s not smart, you might not understand everything because your brain can’t catch up. Don’t try to get everything done as quick as possible, sometimes it causes mistakes

    • @rapemap
      @rapemap 2 года назад +3

      reviewing simple explanation after hours of complicated lesson often give you a new understanding and you feel enlightenment.

  • @sachimoo
    @sachimoo 7 лет назад +411

    I am taking a Statistics class online and YOU are by far the BEST thing I've come across! Your explanations are clear and thorough. You cut through all the STATISTIC jargon and allow the student to conceptualize the theory of basic statistical analyses & problems. You are truly Gifted!Thank you for sharing your knowledge and Passion.

  • @kk8490
    @kk8490 7 лет назад +428

    Oh my god yes. Not all superheroes wear capes

    • @lkerzgrl24
      @lkerzgrl24 5 лет назад +10

      Plot twist: he was wearing a cape

    • @whitewalker608
      @whitewalker608 5 лет назад +10

      @@lkerzgrl24 Plot twist. OP is talking about Iron Man.

    • @kavyasoni139
      @kavyasoni139 4 месяца назад +1

      ​@@whitewalker608plot twist he is talking about Superman 😂

  • @harijsijabs2420
    @harijsijabs2420 9 лет назад +592

    This made so much more sense than my university professor. Thanks a lot!

    • @edthoreum7625
      @edthoreum7625 7 лет назад +4

      great work but #are so small and the board is so dark?

    • @Anonymous-ko5ug
      @Anonymous-ko5ug 6 лет назад +14

      Harijs Ijabs why are you learning this in university? I'm learning this in the 6th grade

    • @FloydFilmz
      @FloydFilmz 6 лет назад +25

      bcuz we all have specific concepts we are learning in college such as criminal justice or law or engineering. But there are a few courses that you have to repeat that u've already learned in middle and highschool. Thats why kid.

    • @azimtwice
      @azimtwice 5 лет назад +4

      +FloydFilmz why'd we pay thousands to repeat what we've already learned?

    • @oliviaso9726
      @oliviaso9726 4 года назад +1

      @@azimtwice idk

  • @krossthug
    @krossthug 10 лет назад +635

    i cried cos this helped me so much

    • @Zmunk19
      @Zmunk19 9 лет назад +4

      did it sound something like trololollololololoololollololol

    • @videogamejo
      @videogamejo 9 лет назад +46

      ***** Right? Isn't Khan amazing? Khan Academy makes me realize that math isn't so bad when explained properly. So many teachers and books explains things in a cryptic manner. Khan explains this stuff in layman's terms and it just clicks.

    • @madrid7790
      @madrid7790 6 лет назад +5

      Did you pee yourself too?

    • @ammaraa3287
      @ammaraa3287 6 лет назад +2

      Same!!! In class I was like what is this even and here I understood it 😂🌸🌸

    • @memoo2133
      @memoo2133 6 лет назад

      JJ not math, its statistics.

  • @coolshante7093
    @coolshante7093 4 года назад +198

    There am I scrolling down and liking every comment coz I can relate to them

  • @0nly1w0rld
    @0nly1w0rld 2 года назад +18

    This guy has done so much on Khan Academy, he should be nominated for the Nobel Prize in Education. If there isn't such a category, they should create one

  • @murators4732
    @murators4732 2 года назад +10

    Please never delete your videos. I am also 10 years after posting learning this stuff and you are the only one who explained it the way i could understand and use it. Youe helped, help and will help millions of people. Thank you

  • @Supremepie
    @Supremepie Год назад +7

    Khan academy... helped my 14 year old self, and still helping me at 24 years old, God bless you.

  • @StopwatchRobert
    @StopwatchRobert 10 лет назад +23

    You know Mr. Khan, you and you alone are the reason this program works so well. What you teach is no different than a university professor, but the way you teach it squeezes more information into a 12 minute video than I'll get in a 50 minute lecture, and I understand it much better. I think I speak for everyone when I say I wish you were my teacher, you'd be absolutely perfect at it.

  • @fabbabs
    @fabbabs 9 лет назад +72

    I have studied these concepts in at least three different classes and never understood them as well as I do now. Thank you.

  • @Lani2722
    @Lani2722 3 года назад +60

    Everyone is talking about their professors in university and how they're useless like 7-2 years ago I'm here in 2020 trying to figure this out in high school because I hate remote learning.

    • @Lillith9008
      @Lillith9008 3 года назад +3

      that sounds very difficult dear, i can't even imagine having to do high school right now. i'm sorry you have to go through that

    • @gracemostek1976
      @gracemostek1976 3 года назад +2

      same

    • @janaaa9309
      @janaaa9309 3 года назад +1

      me too

    • @ikyouknoweknow
      @ikyouknoweknow 3 года назад

      @@Lillith9008 thank u for being compassionate

  • @Notabot2000
    @Notabot2000 5 лет назад +97

    Learned more with this video than the first 3 weeks of college with my useless professor

    • @ZoZo-sk7mq
      @ZoZo-sk7mq 5 лет назад +6

      Hold on you r learning this in Uni then why am i learning this year 9 or 9th grade
      AUstralia IS messed up

    • @herat3158
      @herat3158 5 лет назад +2

      College?
      We're learning this in grade 9 though

    • @ZoZo-sk7mq
      @ZoZo-sk7mq 5 лет назад +1

      @@herat3158 thats what i said but in australia we call college uni

    • @lily-er5xt
      @lily-er5xt 4 года назад +1

      I’m learning this in 7th

    • @gacharaeztrid7620
      @gacharaeztrid7620 4 года назад

      @@lily-er5xt yeah, same.

  • @BrianKouhi
    @BrianKouhi 8 лет назад +62

    Amazing teaching skills, i've struggled to understand this in university for the past 2 months, with my prof being of little use. first time watching this 10min video and i completely understand it now! Thank you!

    • @122willman
      @122willman 6 лет назад +7

      just goes to show these universities are so overrated. they don't teach anymore. About to graduate myself and it is so funny what university teaching has become.

  • @jeremyrodriguez4989
    @jeremyrodriguez4989 3 года назад +1

    Currently a history major with a minor in political science. Took statistics in high school and again in college but this just made so much sense. To anyone reading the comments, watch frequency tables first and then start looking at this video. It takes15 minutes for both but you'll appreciate so much math quickly.

  • @HannanAli
    @HannanAli 3 года назад +1

    If only you guys could see how the teacher teaches this subject at my university...You'd hate this subject i guarantee. She straight up reads solutions from the guide book without explaining whats happening or why we are doing anything.... Thank You So Much Khan Academy!!!

  • @nelsoncastillo7888
    @nelsoncastillo7888 8 лет назад +21

    Your method of teaching is comprehensible, thanks

  • @coreyw2124
    @coreyw2124 4 года назад +3

    You're so clear and cut through the jargon so well that it's actually making me mad. I spent so much time in college trying to understand this stuff and if I would have just watched these videos instead I can't even think about the amount of time and effort I would have saved. Great stuff

  • @josecuervo1646
    @josecuervo1646 5 лет назад +27

    I need Sal to take my SAT for me.

  • @HAMID___
    @HAMID___ 6 лет назад +15

    Thank you u explained it so seamlessly 😭👏🏽. U save me from failing a test

  • @saulmatakarawa9236
    @saulmatakarawa9236 8 лет назад +99

    Very well explained. However, I find another explanation stating that the denominator in variance calculation should be n-1, which in this case should be 4 (5-1=4). Please clarify. Thanks

    • @manveersingh7842
      @manveersingh7842 8 лет назад +22

      +Saul Matakarawa I believe n-1 is to calculate the sample variance.
      Not 100% sure, but from what I remember.

    • @Alex-zc9ty
      @Alex-zc9ty 5 лет назад +1

      somebody else explained please

    • @aoa0687
      @aoa0687 5 лет назад +4

      vortex.ihrc.fiu.edu/MET4570/members/Lectures/Lect05/m10divideby_nminus1.pdf
      Check page 2

    • @pppkaew4297
      @pppkaew4297 5 лет назад +22

      Sample Variance’s denominator is n-1. Population variance’s is n

    • @vijayanandvadhyar7224
      @vijayanandvadhyar7224 4 года назад

      @@pppkaew4297 thanks

  • @yrebrac
    @yrebrac 4 года назад +9

    Khan, you legend. Needed a quick primer on this topic. You are the man.

  • @moizkhalid2714
    @moizkhalid2714 4 года назад +2

    Any time you feel struck in mathematics, you tune into Khan Academy where Sir Sal explaining the concept so easily.Another day is saved,thanks to Khan Academy.

  • @wiifreak911
    @wiifreak911 11 лет назад +2

    This is the "Population Standard Deviation"
    For the "Sample Standard Deviation" we replace n with (n-1) to ensure that all desirable properties of an estimator are retained.

  • @fangtzukang6163
    @fangtzukang6163 2 года назад +2

    The most helpful explanation about standard deviation I've ever watched. Thank you so much, Sal!!!! You're the best math teacher in the universe.

  • @coronnation8854
    @coronnation8854 Год назад +1

    You have been helping me pass university classes for the last decade.
    You're a very important person in the world.

  • @techvishnuyt
    @techvishnuyt Год назад +3

    13 years later, yup learning from here more than my professors

  • @user-zr4od4qg7s
    @user-zr4od4qg7s 4 года назад +2

    I been sick for the past week and my friends told me about this because they are learning at school so I got worried since they said there's a test tomorrow but this helped a lot THANK YOU now I'm ready

  • @marysadek9683
    @marysadek9683 4 года назад +2

    This is amazing! I thought I hated stat until I watched the video. It turns out I have a bad teacher lol . The teacher who made this video made it simple and conveyed the meaning in a great way! Thank you:)

  • @timenotime
    @timenotime 4 года назад

    this is SUCH a good video. i am doing a course in stats for uni and struggling so much because it's been years since i did maths (never been good at it) and i'm so happy i found this video because it's cleared up so much of what was confusing me about this whole SD vs. variance business

  • @Abhishektheunofficial
    @Abhishektheunofficial 7 лет назад +3

    Thank you so much. This is so helpful. I highly appreciate the time and energy taken to prepare this to make this available for free.

  • @sameedsherazi
    @sameedsherazi 3 года назад +1

    I don't know why but I am in love this guy's voice.
    And yeah the lectures being the first.

  • @ntbarnes656
    @ntbarnes656 3 года назад +2

    such a great breakdown!! thank you!! you explained every step so that I understand what I am using to get each answer.

  • @bryanjy7923
    @bryanjy7923 7 лет назад

    From algebra to calculus, to history, and also to statistics?! WoW! so amazed. Is Sal Khan the one that discuss in most these videos? Is he a genius? Or other way around.

  • @gracefredericks2126
    @gracefredericks2126 5 лет назад

    This is so helpful!! THANK YOU. You actually repeat what you're doing to help to get it in our brains and for me, it works! I didn't have to keep scrolling back. (And it also helps that you don't have a ridiculously boring monotone voice like a lot of the people who make these maths videos do)

  • @krishna_kk007
    @krishna_kk007 3 дня назад

    I calculated -20 squared and it was -400. I am not saying you're wrong I just doubt that equation. But other than that you're an amazing teacher. Keep up the excellent work Khan!

  • @mariellesiapno2494
    @mariellesiapno2494 5 лет назад +8

    Thank you so much for this!!!! ♥️ You’re a blessing! ♥️🙌🏼

  • @bsayah
    @bsayah 13 лет назад +5

    Oh my god, this never made so much sense before...thank you so much!

  • @fancydeer
    @fancydeer 2 года назад

    Seriously saving me in my college class. I didn't understand any of this, it's amazing what a difference a GOOD teacher makes.

  • @renatarech2429
    @renatarech2429 5 лет назад

    Oh wow!! I don't normally comment of RUclips videos, but you just took something that I found so confusing and complex and broke down until it was simple! Thank you ever so much

  • @williammagdales2330
    @williammagdales2330 11 лет назад +2

    Dude, now im ready for my periodical test, tommorrow !! I really appreciate you pal !!!

  • @minhazulislam4682
    @minhazulislam4682 3 года назад +1

    hopefully you found that useful... it was the most easiest explanation I got on the internet..My university life started a few months back (online semester ft. Corona) and I am taking a Stat course right now. My teachers explanation was really vague, it's like he(my teacher) is trying to hide something from me. but this actually cleared everything up. Thanks Salman. One day, I will be great teacher like you inshaallah.

  • @silentlessons4221
    @silentlessons4221 Год назад +2

    Khan academy at it again with an awesome explanation and breakdown of statistics. Thanks very much.

  • @pieta39
    @pieta39 4 года назад +3

    I don't have enough words to thank you! You helped so many people, including me. Truly, thanks so much :)

  • @Germel16
    @Germel16 5 лет назад

    Your awesome I completely understand everything. I been having a hard time in this class but I think I understand it a little more now thankx

  • @regineyu34
    @regineyu34 6 лет назад +1

    Your videos really help me get through my statistics class, thank you 💕

  • @MeganMcken
    @MeganMcken 12 лет назад

    I really appreciate these tutorials. I'm not a very logical/math thinker so it is nice to confirm some of my hesitancy.

  • @ninagetmoney9321
    @ninagetmoney9321 6 лет назад

    thank GOD for you!! I was stressing in class. you just made it super simple for me!

  • @aishaabaniel6827
    @aishaabaniel6827 5 лет назад

    Tanx God i found the best teacher here even you tube.nung nag aral ako walan akong naintindihan.thank you so much Sir for your help.God bless u Sir

  • @raquelporras5895
    @raquelporras5895 7 лет назад +3

    Is it just me or does he sound like old Ted Mosby? Great video btw, I've been watching them before class and they are super helpful!

  • @IIXIXOXIXII
    @IIXIXOXIXII 11 лет назад +1

    You spoke at a great pace and very clearly. This video was very helpful.
    I would like to know what the answer to evilshenanegans' question is though.. and william's question on negative numbers and range...

  • @samizaki7165
    @samizaki7165 7 лет назад

    The perfect way to understand the variance and the standard deviation ... Thanks KHAN Academy

  • @ExploreLearnEnglishWithGeorge
    @ExploreLearnEnglishWithGeorge 3 года назад +2

    a video explaining sample variance and population variance would be helpful.. (my synapses are shutting down)

  • @danamclemore3805
    @danamclemore3805 4 года назад +3

    You rock - as usual.
    You are sooo amazing.how many people have you helped ???
    You will never know

  • @jekamiahruiz6500
    @jekamiahruiz6500 5 лет назад +3

    This is cool. You have helped me a lot. Thanks to you 😊
    I've also watched your videos on several topics in physics. Galing nyo po!

  • @xsauce3858
    @xsauce3858 6 лет назад +2

    I was out of class with my friends when my lecturer was teaching this thank you so much.

  • @hoomanazizi8969
    @hoomanazizi8969 Месяц назад

    I studied finance in uni and our master could not explain it as simple as this in a whole semester. thanks

  • @hugojj101
    @hugojj101 6 лет назад

    Ha, watched Khan academy vids when I was 10 and here I am 6 years later using them to help me with my as levels

  • @trombonetribute6433
    @trombonetribute6433 5 лет назад +1

    It's summer I'm 13 and I'm learning it's my best summer yet
    I understood standard deviation from my math book I just didn't see that variation was standard deviation without it being square rooted it's so easy

  • @kevinrandalrulach
    @kevinrandalrulach 2 года назад

    I know these stuff 100%, but I need to understand these stuff with 300% confidence. Thanks for the upload.

  • @Naked_Snake
    @Naked_Snake 12 лет назад

    Haven't really used Khan Academy before, but I used this for Economics and makes perfect sense. Thank You.

  • @muhammedrajab2301
    @muhammedrajab2301 3 года назад +2

    Awesome video and great explanation. But one quick correction, 9:48 Distance can't be negative or zero.

  • @sabrinadiego3586
    @sabrinadiego3586 5 лет назад

    You did a great job. I followed the lecture and I could not understand. I saw your video only once and I realize that it is very easy. I think because you explain very well. thank you very much.

  • @saadhashmi7953
    @saadhashmi7953 2 года назад +1

    Found this vedio in my 3rd year of med school and was saved in Biostatistics. Alhamdulillah

  • @waterfairy2011
    @waterfairy2011 9 месяцев назад

    First time in my life I understand what is variance. Thank you so much!!!

  • @eduugr
    @eduugr 6 лет назад +1

    Thank you. You are really good explaining !!

  • @hariiiprasath
    @hariiiprasath Год назад

    Here I am, trying to actually understand these concepts 8 years after school, and this 12 min video made me feel like my schooling had failed me.

  • @djchillsbx1
    @djchillsbx1 11 лет назад +1

    yes indeed this explians it a bit better than all the other class material. Thanks!

  • @gurpreetbhalla
    @gurpreetbhalla 13 лет назад +1

    your videos are too good and i think u are doing a great job

  • @bcasarez
    @bcasarez 12 лет назад

    The video is correct because he dealing with a population data set (also evident by the use of the sigma symbol). He explains this @ 4:45 - 5:09. You only use (n-1) when you are dealing with a sample data set (where you use "s" and not sigma).

  • @Mahmoud-ys1kt
    @Mahmoud-ys1kt Год назад +2

    Simply , Its Great . Thank you

  • @denzilseukanundun540
    @denzilseukanundun540 2 года назад

    I need this channel for Data Science! Thank you Khan Academy!

  • @88spaces
    @88spaces 4 года назад +1

    Your explanation is very clear and simple to understand. Thank you.

  • @tasbeehdeyaa
    @tasbeehdeyaa 3 года назад

    Thank you so much. This.. This is exactly what I needed. It made me realize I'm not slow nor stupid it just depends on who the teacher is.

  • @kishwarbhuiyan743
    @kishwarbhuiyan743 3 года назад

    This video has helped me a lot to understand standard deviation and variance.Thanks a lot Khan Academy.

  • @Czathero
    @Czathero 11 лет назад +4

    OMG! I love you! I finally understand this now!
    So happy!

  • @philosophize24
    @philosophize24 6 лет назад

    thank you, Khan Academy. you are saving me from failing stats.

  • @mbkfox
    @mbkfox 12 лет назад +2

    you are an amazing individual, thanks for making it simple

  • @abdulrahmankaka
    @abdulrahmankaka 11 лет назад +1

    now i get it thank you very much !

  • @A11Omar
    @A11Omar 11 лет назад +3

    very useful. I'm taking QUAN201 and I wish I had you as my instructor 'cause mine really sucks

  • @samanthapikus3178
    @samanthapikus3178 7 лет назад +1

    For the square root of 200 I get 14.142... How am I understanding this wrong... Great video. You are a really good explainer.

  • @kimsrenglim
    @kimsrenglim 6 лет назад

    Vous êtes merveilleux! Merci!

  • @marj736
    @marj736 7 лет назад +3

    Khan, you are a life saver!

  • @jednx01
    @jednx01 13 лет назад

    Everybody, please check your formulas. This video is almost correct, but he forgot that it's supposed to divide by (n-1). That means that the whole thing should be divded by 4, not 5 for the variance problems.

  • @watchlearn3943
    @watchlearn3943 2 года назад

    Well explained. Now I was able to relate all these things. Thank you very much.

  • @ioannismarkoulakis4978
    @ioannismarkoulakis4978 6 лет назад

    I normally just like the video but, this one deserves a comment. Good job, great explanation!

  • @Neutrino22
    @Neutrino22 6 лет назад

    Your every videos on mathematics is awesome. I have learned so many things. Love youuu

  • @XinhLe
    @XinhLe 7 лет назад +3

    Thanks so much (from Southern hemisphere)!

  • @adelinaa1366
    @adelinaa1366 9 лет назад +1

    it really helped me! Thanks a lot!

  • @parassingh6347
    @parassingh6347 6 лет назад

    I got this blody mean deviation ....all thanxx goes to u sir ....

  • @saravaliyeva2591
    @saravaliyeva2591 8 месяцев назад

    Thank you so much for your video and explanations .I started Statistics classes recently and i also learn more from here than from my professor .It helps really thanks a lot again

  • @alinamanha1561
    @alinamanha1561 5 лет назад

    Simply amazing! Really really proud of you , Khan (as a Bangladeshi)!

  • @hubdarali8633
    @hubdarali8633 3 года назад

    I have learned this topic different videos lecture but your lecture is conceptualize and clear my all confusion...thanks❤❤

  • @AissatouDiallo-qh7he
    @AissatouDiallo-qh7he 6 лет назад +1

    It seems very clear and helpful
    Thanks so much

  • @AbdulazizMaiof
    @AbdulazizMaiof 7 лет назад +1

    Thaaanx

  • @ezzrivera1355
    @ezzrivera1355 6 лет назад +1

    Thank youuu omg I can take my exam tomorrow in stat without any doubts with my answers

  • @Yud_Trinitarian
    @Yud_Trinitarian 4 года назад

    1. explain how you determine if a graph has high or low variability
    2. Explain how you determine if a graph has high or low statistical bias.
    3. Explain the difference between stratified random sampling and cluster sampling.

  • @brokenballer89
    @brokenballer89 5 лет назад

    OMG this clip..... how can you explain these things in such a easy way. Thank you!!!

  • @sindizwane7482
    @sindizwane7482 2 года назад +1

    I love your explanation really but I am bit confused with SD (standard deviation) but I will go back toy book and listen to this again. Thanks 🙏🏿

  • @ayeshafaiz3582
    @ayeshafaiz3582 5 лет назад

    Thanks Allah that khan academy axist on youtube..so much helpful.such a great explanation..