ck12.org normal distribution problems: z-score | Probability and Statistics | Khan Academy

Поділитися
Вставка
  • Опубліковано 13 січ 2025

КОМЕНТАРІ • 149

  • @berry.x9388
    @berry.x9388 5 років тому +204

    "how many standart deviatons away from the mean"
    this simple explanation was all i needed. my "proffessor" who has "worked on biostatistics for 30 years" tried to explain this to us for 25 mins and when she couldnt she accused us of not knowing any math. thank you for the video, khan academy

    • @Chloe-gh6mg
      @Chloe-gh6mg 4 роки тому +3

      True. I just come here after my STAT online lecture(my prof is well-known for the bad teaching skill🤦🏻‍♀️

    • @berrie7098
      @berrie7098 2 роки тому

      literally here taking biostatistics as my first stats class ever an couldn't agree more!! that one sentence was sooo needed to put it all together !!!

    • @maykaa4000
      @maykaa4000 2 роки тому +2

      lmao yea just blame it on the teacher

    • @danal8246
      @danal8246 Рік тому +6

      @@maykaa4000 Ur watching the same video bozo

    • @layth.rokage4943
      @layth.rokage4943 Рік тому

      thats hilarious🤣 @@danal8246

  • @bethmacdonald176
    @bethmacdonald176 9 років тому +521

    I cried while watching this video because it FINALLY made sense. I've been trying to figure this out since the beginning of the semester and you made it so clear. Thank you. Thank you. Thank you.

    • @imamulmalikchowdhury7659
      @imamulmalikchowdhury7659 7 років тому +3

      You learn this in university ?

    • @schanemassey3861
      @schanemassey3861 7 років тому +18

      Yes! This is taught most lower level math university classes :) I'm guessing you learned this in 2nd grade huh? #aren'tyouaGeninus

    • @traviswilson36
      @traviswilson36 6 років тому +3

      You must have not learned grammar though

    • @nitamac1312
      @nitamac1312 6 років тому +7

      lmfao why are you flaming him soooo hard?!?

    • @sophikolomineishvili7109
      @sophikolomineishvili7109 5 років тому +1

      @@schanemassey3861 yes it is taught at Universities, even at grad level. However, depends on your major, I personally study this in my research and analysis class, I don't think I ll ever use it in real life :)

  • @ayannabrown7303
    @ayannabrown7303 9 років тому +74

    I know you get a lot of comments thanking you, but I don't think you understand how much I genuinely appreciate you!! I've been watching your videos since my freshman year in college and you've helped me tremendously. Thank you. God bless your heart.

  • @TriniSecularHumanist
    @TriniSecularHumanist 9 років тому +15

    I cannot begin to thank you for simplifying what I have been doing in class for the past month! Thank you for explaining what z-squared means!!! We were taught how to calculate but not what it means. I just experienced multiple epiphanies. Thank you so much for sharing your knowledge online for free! The world is a better place for it!

  • @shayanahmad1451
    @shayanahmad1451 10 років тому +127

    I learned more from your videos than from my entire time in colllege

  • @fnmav
    @fnmav 5 років тому +32

    3:50 "Let's do a couple more, let's do all of em" Love the attitude ! :D

  • @rachelchu5363
    @rachelchu5363 4 роки тому +11

    I cried. Imagine if i learnt statistics from you, i would get my statistics 100% mark. Thanks for contribution. A great teacher is the most notable role.

  • @praptiadhikari9054
    @praptiadhikari9054 8 років тому +40

    your videos are so much fun
    and appreciated by everyone
    classroom lectures make us yawn
    all we wanna say is thank you Khan

  • @pawality5725
    @pawality5725 11 років тому +7

    This is the best example I found yet. I am still struggling with with STATS and this has open my eyes up a little more. Thanks a lot

  • @scottparsons7825
    @scottparsons7825 5 років тому +5

    Once again you have taken a concept that was presented in a confusing manner in my book and made it ridiculously simple! Thanks!

  • @sofiapraderio7441
    @sofiapraderio7441 4 роки тому +4

    I watched countless videos about this and this one was the one that truly made me understand this perfectly. thank you SO much!!!

  • @WhatIsThatBlueStuff
    @WhatIsThatBlueStuff 12 років тому +17

    I went from stressing out to acing stats thanks to this guy

    • @barbaradonohue4822
      @barbaradonohue4822 Рік тому

      Ten years. It’s been ten years. Still remember? Lol. I’m just learning 😢 7:47

  • @Anam7145
    @Anam7145 12 років тому +5

    Mr. Khan always explains my one hour lecture classes in less than 15 minutes. Awesome.

  • @sampleaccount789
    @sampleaccount789 6 років тому +2

    This is my first video and I have fall in love with Khan Academy. Dude you are super awesome. Keep going.

  • @TheMunkzilla1
    @TheMunkzilla1 Рік тому

    Thank you. This finally makes sense. Textbooks over complicate things and when taking statistics courses online with no actual classtime this is a lifesaver!

  • @Richard24Blair
    @Richard24Blair 15 років тому

    I'm attempting (and until recently, failing) to take Statistics right now, and you are a god to me thanks to these videos.

  • @greymollusk
    @greymollusk 10 років тому +4

    Khan is the stuff of legends!
    All Hail Khan!

  • @MiguelBandito1988
    @MiguelBandito1988 11 років тому +9

    Thanks Professor.. You made this so simple.

  • @Momofwaterchild
    @Momofwaterchild 13 років тому

    My statistics professor knows his stuff but cannot teach in a clear and simple method, which these videos do. So, thank you very much, you have helped tremendously!

  • @QuillWorks
    @QuillWorks 5 років тому +14

    0:22
    My ears: “A mean of 81”
    My head: “A mu of 81”

  • @haleywang8941
    @haleywang8941 6 років тому +60

    why can' t college be khan academy

    • @benjaminroscoe3690
      @benjaminroscoe3690 4 роки тому +5

      it kind of is now... this aged really well

    • @haleywang8941
      @haleywang8941 4 роки тому +3

      @@benjaminroscoe3690 LMAO I forgot that I had written this

  • @DoomScrollerPLUG
    @DoomScrollerPLUG Рік тому +2

    Even after 13 years it’s still helpful because my professor is so quite I can’t hear half the things he says 😂

  • @Sheena000
    @Sheena000 5 років тому +3

    Bless you sir. Final exam is tomorrow and I have to learn the last unit rn.

  • @charlescapehart3556
    @charlescapehart3556 Рік тому

    Thank you!!! I swear they made this so difficult for no reason!!!!!

  • @juan57547
    @juan57547 10 років тому +39

    Man your handwriting is nice

  • @Th30bserver
    @Th30bserver 13 років тому +1

    Thank you so much. This saved me from wasting my no-homework pass on a easy concept.

  • @celiaalcantara4651
    @celiaalcantara4651 3 роки тому

    I believed I WOULD NEVER understand this formula to calculate z scores and I just GOT IT! I BOW TO YOU SIR!!

  • @michikosmith3262
    @michikosmith3262 4 роки тому +1

    Every stats prof needs to just make this video part of their lecture

  • @gabyaguilar3552
    @gabyaguilar3552 7 років тому +1

    I'm pretty sure that I'll get an A in my math test tomorrow. Thank you so much!!

  • @Naturenest7-v6k
    @Naturenest7-v6k 3 роки тому +1

    thank you so much, you are the best math teacher I have ever met! 🙏❤️

  • @danielaalmendaro8470
    @danielaalmendaro8470 7 років тому +3

    Thanks for the help my final is tomorrow and I’ve been studying this whole week since it has to be accumulative🙄

  • @genresanfuego4314
    @genresanfuego4314 6 років тому +2

    He is a better teacher than my math teacher😑

  • @angelicamontanez8372
    @angelicamontanez8372 Рік тому

    Here is to this still being absolutely amazing

  • @gorgjesss
    @gorgjesss 7 років тому

    pretty helpful, this stuff is going to be on my final exam. It is pretty new to me, but I have been getting it with the help of drawing the bell curve and the z-score formulas. so thank you for all your simple explanations and help!

  • @KCTOOREAL
    @KCTOOREAL Рік тому

    God bless khan academy🙌🏾

  • @T_Acc
    @T_Acc 2 роки тому

    You are a blessing on earth

  • @Lizdepina
    @Lizdepina 12 років тому +1

    I think I'm in love with you....You are a statistics GOD! Thank you!!!!!!!

  • @Bapewatch01
    @Bapewatch01 13 років тому

    thank you !! wen u describe each step properly i understand wat ur saying, u r cool :D

  • @CiscoBerrones
    @CiscoBerrones 7 років тому

    Finally it makes sense!!! Thank you for this video!

  • @chittiprolurammohan2415
    @chittiprolurammohan2415 11 років тому

    That is Khan! Great Bro! u unclose my doubts in Z score definition= no of Sd away of mean!

  • @lizzchoate
    @lizzchoate 13 років тому +1

    Please help me figure this out....I need your amazing teaching skills!!!
    On a standard measure of hearing ability, the mean is 300 and the standard deviation
    is 20. Give the Z scores for persons who score
    (a) 340
    (b) 310
    (c) 260
    Give the raw scores for persons whose Z scores on this test are
    (d) 2.4
    (e) 1.5
    (f) 0
    (g)-45

    • @pratapkumarmishra8297
      @pratapkumarmishra8297 6 років тому

      a) 2
      b) 0.5
      C) -2
      Use formula:
      (X-u)/c=z
      U= mean and c=standard deviation.
      In first three cases x is in options and z is to be calculated. Reverse in next three cases

  • @sunshinegamas331
    @sunshinegamas331 6 років тому +1

    Thank you very very much i am smart in math i am bullied because of this thanks because i find this thank you very much😭😭

  • @ZachGRocketBossZach
    @ZachGRocketBossZach 11 років тому +3

    Kahn, you're great; I just wish your videos were louder.

  • @nikhiljoyappa687
    @nikhiljoyappa687 4 роки тому

    Excellently explained 👏

  • @71318elmo71318
    @71318elmo71318 14 років тому

    Thankyou, exam tomorrow, big help!

  • @Johnny.bar99
    @Johnny.bar99 5 років тому

    why am I paying for university, I'll just subscribe to this guy and put it on my resume

  • @nubianmaat3322
    @nubianmaat3322 2 роки тому +3

    Who ever you are teaching this concept, I hope the gods smile on you lol! Why is it that no one could explain this the way you did!? Thank you so much for having the ability to teach as if you're teaching a child! You are so awesom!

  • @brampyvich
    @brampyvich 10 років тому

    Great Video, Thanks Khan...

  • @AhJodie
    @AhJodie 4 роки тому

    Sal, you are so brilliant!!!!!

  • @not_allure5283
    @not_allure5283 3 місяці тому

    IM GONNA CRY TJANK YOU SO MUCH

  • @Iamatheist1234
    @Iamatheist1234 12 років тому +1

    hes' a science and math god.

  • @MsPerva
    @MsPerva 8 років тому +1

    You are the best 🌹🌹🌹

  • @Alison7292
    @Alison7292 8 років тому +1

    OH MY GOODNESS. Thank you

  • @lolscience1979
    @lolscience1979 5 років тому

    All the ninth graders in Honors Algebra 2 will thank you this night before the quiz!

  • @Polo-715
    @Polo-715 2 роки тому

    I think I learn better through videos not gonna lie

  • @JakeLo1991
    @JakeLo1991 Рік тому +1

    ALL YOU NEED IS DESIRE.

  • @kellytones9104
    @kellytones9104 6 років тому +1

    Thank you soo much, perfect

  • @stevenconner3417
    @stevenconner3417 5 років тому

    Let's use a z-score in statistics for Optometry so that all C interfaces private and public for example time clocks when someone is 50 years old they don't have to use the readers to do the same job

  • @cottonjun01
    @cottonjun01 3 роки тому

    Thank u so much 💓 😭

  • @jeromepringle4949
    @jeromepringle4949 Рік тому

    Great video!

  • @paulhetherington3854
    @paulhetherington3854 2 роки тому

    6.3? 6+-3 = 9:3 = 12:6 - calculus rules: Laarjist till lilist

  • @kare917
    @kare917 Рік тому

    Thank you ❤

  • @andrewl1024
    @andrewl1024 8 місяців тому

    WOW! Mind blown.

  • @majormuss
    @majormuss 14 років тому

    can't thank you enough.. keep it up!!

  • @eainpower5670
    @eainpower5670 Рік тому

    good explanation

  • @raymersonjaymesduad720
    @raymersonjaymesduad720 Рік тому

    It all makes sense now
    The pieces are falling into place

  • @onyxora
    @onyxora 5 років тому

    If a z-score is a measure of how many standard deviations from the mean, does it matter if your results are "normal" (bell curve) or can they be skewed right or left and still use the z-score to identify if data is more unusual based upon distance from the mean?

  • @pblack68
    @pblack68 11 років тому

    Love your handwriting

  • @paulceltics
    @paulceltics 13 років тому

    thanks man this saved me

  • @hoduonghai7936
    @hoduonghai7936 5 років тому

    My FAVOURITE channel from now on, unsubcribed every other channels, thank you x 99

  • @noobkosh
    @noobkosh 11 років тому

    another saviour video

  • @shades45501
    @shades45501 12 років тому

    thank god i needed this

  • @teachersimprint
    @teachersimprint 11 років тому

    Thank you. Clarification!

  • @franklincarpenter5431
    @franklincarpenter5431 10 років тому

    Thank you!

  • @Zaloomination
    @Zaloomination 7 років тому

    This is great, my class's powerpoint presentation made NO sense. Why can't they explain it in clear terms like Khan?

  • @VanessaLopez-xo4yo
    @VanessaLopez-xo4yo Рік тому

    Found this video very helpful as it will be on my CPCE exam for graduation! I’m just a little confused regarding the answer (A). Is it because it’s closer to the mean? Sorry I know it’s a very silly question and yes the video was helpful I just don’t understand why (A) is the answer ! 🥺 please help 🙏🏼

  • @myenmoni
    @myenmoni 13 років тому

    You are awesome!

  • @joannemamo8177
    @joannemamo8177 7 років тому

    Amazing thanks

  • @Hendrixtv44
    @Hendrixtv44 9 місяців тому

    Sir I would like to ask a question. I see the answer for c gave us a decimal. Does it mean in Z-score Normalization we can't round up the decimals? Please I am new and which to know more. thank you.

  • @murridithvines
    @murridithvines 11 років тому

    Thank you!!!

  • @shetsangtenzin
    @shetsangtenzin 5 років тому

    5 minutes is all it took for me to understand the concept watching this video and my class professor took 3 class session on z score and yet failed

  • @The4416deb
    @The4416deb 7 років тому

    Thank you

  • @oiiirich
    @oiiirich 11 років тому

    I hate statistics but Sal makes it cool. :)

  • @jababyxd
    @jababyxd 13 років тому

    Big help!!! thank you :-)

  • @axe3329
    @axe3329 2 роки тому +1

    It was this easy all along???

  • @justme-iv5yq
    @justme-iv5yq 4 роки тому

    Now you’re talking my language

  • @JustHuman8
    @JustHuman8 12 років тому

    wish i found this before my final exams :(

  • @MizzC625
    @MizzC625 4 роки тому

    Yaaassss!! *lightbulb*

  • @INSANExSAMURAI
    @INSANExSAMURAI 12 років тому

    How do you know when its negative or positive, cause on A you did -16 but on B you did positive 2 so how do I know if its positive or negative?

  • @kyrahdames8215
    @kyrahdames8215 6 років тому

    what is the formula before solving random numbers in

  • @chariots8x230
    @chariots8x230 4 роки тому

    What I don’t understand is how you mapped these z-scores on the bell curve. How can I calculate exactly where each one belongs on the bell curve?

    • @victor_peral
      @victor_peral 3 роки тому

      Multiply the z score value by the standard deviation it gives the exact value from the mean

  • @stevegrca
    @stevegrca 14 років тому

    wow. thanks a lot

  • @VleerLab
    @VleerLab 12 років тому

    Good for you.

  • @LTS720
    @LTS720 3 роки тому

    Khan Academy: Z-score is the number of standard deviations away from the mean.
    Text Book: The Z-score is the distance between two points divided by X, multiplied by a goose and the square root of a turkey sandwich on top of a moving train car while being juggled by a clown.

  • @Fsp01
    @Fsp01 6 років тому

    Life saver.

  • @fadwa2413
    @fadwa2413 3 роки тому

    i love you man

  • @praptiadhikari9054
    @praptiadhikari9054 8 років тому

    why do/how can exam grades follow normal distribution?

  • @johnydoe9167
    @johnydoe9167 Рік тому

    bro it sounds like Scott Cawthon's voice acting before fnaf

  • @CloudGOML
    @CloudGOML 6 років тому +1

    Salman Khan is KINGGGGGG

  • @shazaduh
    @shazaduh 15 років тому

    love it.