Discrete and continuous random variables | Probability and Statistics | Khan Academy

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  • Опубліковано 22 гру 2024

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  • @Zhim94
    @Zhim94 5 років тому +1239

    For those who don't quite understand, discrete R.V is for counting; continous R.V is for measuring.

    • @abhineelnandi8211
      @abhineelnandi8211 4 роки тому +129

      Entire Video in a single line.

    • @notjin2109
      @notjin2109 4 роки тому +12

      what’s the difference between counting and measuring

    • @user-en5gm1vw3c
      @user-en5gm1vw3c 4 роки тому +61

      @@notjin2109 counting means for example we count monthly income of a person but we will not measure that... Same way we measure the weight of a person but we don't count that

    • @notjin2109
      @notjin2109 4 роки тому +8

      1234 5678 I would like a difference that doesn’t rely on examples because i can’t think of a difference that linguistically matters

    • @anaforero6108
      @anaforero6108 4 роки тому +37

      ​@@notjin2109 Discrete is a word used to refer to something that can have "separate fixed values", one example is integer numbers. Continuous is a word to refer to things that are difficult to assign a separation between two things (values), or in other words: that separation can be neglected (one number is exactly next to the other number).

  • @judsonl8990
    @judsonl8990 4 роки тому +706

    I'm going to COVID's version of a university right now - these Kahn Academy videos are way more helpful than my stats professor.

    • @cashele
      @cashele 4 роки тому +9

      tell me about it!

    • @pradipteeshrestha4097
      @pradipteeshrestha4097 4 роки тому +21

      I'm not in college, but I am a senior taking an AP Stats course and my teacher isn't much help, so I agree! It's my worst class this year and never understand what's happening.

    • @briantarrant4907
      @briantarrant4907 4 роки тому +2

      no kidding

    • @andrewperez8190
      @andrewperez8190 3 роки тому +1

      bruh for real..same

    • @arianachu9834
      @arianachu9834 3 роки тому

      me either

  • @mainguy5387
    @mainguy5387 Рік тому +90

    I asked Chat GPT to explain like im 5 years old
    "Alright, imagine you have some marbles. Discrete variables are like counting how many marbles you have. You can have 1 marble, 2 marbles, 3 marbles, and so on. Each number is separate and you can't have half a marble or a quarter of a marble.
    Now, think about a jar of water. Continuous variables are like measuring how much water is in the jar. You can have a little bit of water, a medium amount, or a lot, and you can also have in-between amounts like half-full or one-third full. There's no limit to how much water you can have, and it can be any amount, not just whole numbers.
    So, discrete variables are like counting marbles, where you can only have whole numbers, and continuous variables are like measuring water, where you can have any amount, even parts of it."

    • @delglory5494
      @delglory5494 3 місяці тому +1

      Excellent, thank you

    • @AVPDS99
      @AVPDS99 Місяць тому +1

      Thank you sooooo much ❤

  • @DerrickTay88
    @DerrickTay88 8 років тому +258

    I dont usually comment on such videos. But this is way too easy to understand from his explanation. I would have A's any class if all my lecturer are like him. Thumbs Up !!!

  • @pearcei
    @pearcei 10 років тому +483

    we spent a whole day on just the definition of discrete vs continuous variables in class and i still didn't know it and then i learned it in less than 3 minutes here

  • @FortniteJoe123
    @FortniteJoe123 2 роки тому +12

    I like the small snippets of commentary that are added into the lesson, like ants learning interstellar travel and how Usain Bolt is aging. It makes the video so much more fun to watch lol.

  • @khushigupta5904
    @khushigupta5904 11 місяців тому +7

    Khan Academy, you guys are doing a wonderful job. I was feeling dumb in class when it came to this topic but now I understood everything. Sad to see how the classroom learning doesn't help most of us.

  • @khanacademy
    @khanacademy  12 років тому +18

    Good question. It is not a question of the size of the population you are sampling from. It is a question of the possible values that each sample can take on. Mass can take on any value (including an irrational number if we don't get caught up with quantum mechanics) so it is a continuous random variable.

  • @AIONBERSERKER
    @AIONBERSERKER 9 років тому +31

    My professor made this whole thing seem so complicated. You explained it in less that 15 minutes :D

  • @thinkfeelsolve
    @thinkfeelsolve 5 років тому +34

    Thank you, sir.
    Discrete random variables cannot be broken down into decimals or fractions.
    There is no half an ant or half a person. but there can be half a second and one-fourth of a meter.
    Discrete things are counted.
    continuous things are measured.

  • @cashele
    @cashele 4 роки тому +84

    "the New Orleans zoo where I grew up" lmaooo

  • @mithurajdas225
    @mithurajdas225 4 роки тому +7

    a good example of continuous random variable:Reading the temperature of a room throughout the day ,its continuous since the temperature does not jump from 20 degrees to 22 degrees.so its continuous process.

    • @davidthomas9276
      @davidthomas9276 10 місяців тому

      Right. And that is the problem I have with the zoo animal mass example. The masses do jump from one to the next,. They do not take on every value within the range. If you plot the masses, they are distinct, separate points. Thus, to me, the variable is discrete.

  • @tarunt9153
    @tarunt9153 2 роки тому +7

    Just looked it up, the teacher was pretty much on point, elephants range from about 2,000-7,000 kg.
    (4,000-14,00 pounds)

  • @thomasip9938
    @thomasip9938 8 років тому +13

    You are a lot clearer than my teacher!

  • @TheIanmurphy
    @TheIanmurphy 10 років тому +21

    Bacterium is the singular form of the noun, and bacteria the plural form - always learning new stuff when I watch your videos!

  • @pervertbismarck5067
    @pervertbismarck5067 4 роки тому +49

    I learnt more in 11 minutes than 1 months. We need more teachers like him.

  • @Chloe-jz4pr
    @Chloe-jz4pr 4 роки тому +7

    Thanks for this video!! I was learning these definitions through online school due to quarantine and I just couldn't understand it. But this video helped me to finally get it. (:

  • @andrewzhu5294
    @andrewzhu5294 7 років тому +8

    When I read the textbook on this topic, it just made my brain literally hurt. But when Khan explained this same exact topic, I understood it completely and I swear my brain relaxed.

  • @s_kaukab
    @s_kaukab 3 роки тому +5

    That was one good explanation, I've always stumbled upon how the heights or weights in a class are not discrete random variables, thanks Sal!

  • @skatershawn410
    @skatershawn410 8 років тому +12

    Love how he called out Bolt would win in the 2016 Olympics!

  • @amalnazir8140
    @amalnazir8140 3 роки тому +11

    Why is no one talking about when he said “maybe some ants have figured out some interstellar travel” 😂 7:58

  • @alfianabdulhalin1873
    @alfianabdulhalin1873 8 років тому +30

    LOL! Polite variables... Thanks for the great vids tho! Helps a lot with the fundamentals!

  • @Z-eng0
    @Z-eng0 3 роки тому +1

    10:10 "Well I guess they're limited by the speed of light" lol

  • @HopeAndrea_HFG
    @HopeAndrea_HFG 3 роки тому

    Thank goodness I came across this video. Why is my textbook so ridiculously hard for no reason?! Serenity NOW!

  • @Nachiket_upadhye_23
    @Nachiket_upadhye_23 4 роки тому +1

    Sal and grant will be invisible pillars of the foundation of next generation mathematicians. 100 years from now, people might forget about you but you would have created 1000 of mathematicians by then

  • @chinanumberone7723
    @chinanumberone7723 5 років тому +3

    Argued this with my friend today and he kept saying I was wrong when I was saying continuous is where it is like an irrational number, they can have no ending, no precise number, or infinite values within two numbers, I knew I was right

  • @reeceperry2237
    @reeceperry2237 Рік тому

    Glad to hear you are from New Orleans. Currently studying for my stats final at Tulane.

  • @jonathanlind5725
    @jonathanlind5725 10 років тому +4

    Very good explaining, I've had a hard time distinguishing the difference between disc. and cont. variables and you managed to tackle the very questions I had. Thank you!

  • @PolskaBabii
    @PolskaBabii 8 місяців тому

    I have been using your videos for quite some time! Cant believe you are from New Orleans! Awesome

  • @elizaeliza3907
    @elizaeliza3907 9 місяців тому

    This is a very good explanation. My lecturer used the same examples as yours, probably watched ur video and I still couldn't understand. Now all is crisp clear

  • @deborahachor9831
    @deborahachor9831 8 років тому +1

    thanks a lot,i was reading my course material and i did not understand anything.but with this video there is clarity and simplicity

  • @bibekanandabhattacharjee952
    @bibekanandabhattacharjee952 3 роки тому

    You are just too good at explanation. You are so articulate. Please continue with your style of teaching and don't get distracted by your critics. If there is one person who dislikes your style there are 100 others who like your lectures. Please carry on. I now know what is a RV. :-D

  • @user-zw3rg2go4o
    @user-zw3rg2go4o 8 років тому +1

    استفدت كثيرا 👍+ صوتك رائع ما شاء الله. thank u so muce

  • @the_growth_mindset.
    @the_growth_mindset. 5 років тому

    I honestly don't know where I'd be without you Sal !

  • @somber087
    @somber087 Рік тому +1

    These short and free videos help me more than my paid teacher in an hour

  • @ranaabdullahranaabdullah3296
    @ranaabdullahranaabdullah3296 3 роки тому

    I love you sir so much.
    I search from morning about some concepts like what is difference between Summation and integral. I watch your and other channnels vedios and also read 9 10 articles.
    I actually want to know that why summation is discrete and integral is continuous . I actually know that what does it mean that value is discrete and that function is continuous. I also know that why we take time approach to 0 in differentiation.
    So I searched and I found that basic after 4 hours search
    Thank you for clear my one concept and doubt.

  • @ahlamadel5467
    @ahlamadel5467 5 років тому +1

    Your handwriting is beautiful!
    Here is a student from Saudi.
    Thanks.

  • @vladimirprotein3275
    @vladimirprotein3275 9 місяців тому +1

    10:50 what if I wanted to round off the time taken to the nearest quadrillionths, would it still be discrete or continuous? (even though the value is in the range of 9-10)

  • @princessmeimban8244
    @princessmeimban8244 4 роки тому

    I thought i lost hope in understanding the discrete and continuos r.v ....then i watched this video!! IT WAS SO EASY to understand thanks

  • @deathsangel123
    @deathsangel123 10 років тому +1

    Thank god for your videos! Have my stats final on Monday and this really helped me understand what is going on.

    • @RB3Vids
      @RB3Vids 10 років тому

      Thank Science

  • @miyamorgan297
    @miyamorgan297 3 роки тому +1

    Some infinities are bigger than other infinities 7:12

  • @mariachow4353
    @mariachow4353 8 років тому +10

    lol when he said, "discrete can mean polite. we are not talking about random variables that are polite."

  • @manmohansingh8211
    @manmohansingh8211 5 років тому +5

    I really wish my lecturer were close to being this good at teaching

  • @SaraAhmed-fp1vi
    @SaraAhmed-fp1vi 6 місяців тому

    Hello, I am a student from Iraq, and I study mathematics in the College of Science. I love mathematics very much, and your channel is also very wonderful. Continue like this.🤍

  • @elizabethafu8182
    @elizabethafu8182 8 років тому +2

    This video helped me so much thank you wish you were my professor! thank you thank you thank you!!!!

  • @thewilloffire4335
    @thewilloffire4335 3 роки тому

    He summed up Statistics in 1 Video...This is where statistics begin

  • @mrjrpnls829
    @mrjrpnls829 2 роки тому

    You explained every details, you are better than my subject teacher ily 😭❤

  • @pinkflower4424
    @pinkflower4424 7 років тому +2

    Thank you khan academy very much 😍😍😍

  • @sumit121285
    @sumit121285 4 роки тому

    its definitely clears our confusion in between discrete & continuous random variables..... thankyou sir , thankyou so much....

  • @nathamha
    @nathamha 7 років тому

    In the lecture I attended, the teacher said the best way to tell the diference is to see if the numbers the random variable takes are natural numbers then it's likely a discrete variable, on the other hand if the value the random variable takes is a real number then it might be a continous random variable.

  • @AlexzandrSpringvale
    @AlexzandrSpringvale 11 років тому +11

    9:10 "It probrably be Usain Bolt, but it may not be. Actually he is again a little bit." That's classic Salman Khan.

  • @mayankbhandari3536
    @mayankbhandari3536 7 років тому +1

    I personally think that Discrete random variable can be identified by a simple test as following, "If bound in a range given by two finite numbers, if the random variable takes infinite values then it cannot be a discrete random variable".

  • @gym5959
    @gym5959 2 роки тому +1

    The exact winning time is continous as a consequence of the uncertainties in the measuring devices , so the winning time can never be measured accurately (because we can never have a instrument without uncertainty in its measurements). Thus the winning time will always be bounded to some interval how ever small it maybe it has uncountable number of infinite values thus it is a continous variable.

  • @designhub360customapparel
    @designhub360customapparel Рік тому

    Thank you! I was about to drop this Business Analytics course at Udacity..

  • @ag6194
    @ag6194 4 роки тому +5

    @khan’s academy: What about age? Is it discrete or Continuous or will it depend on how it is expressed?

    • @The_Mr_Avocado_Man
      @The_Mr_Avocado_Man 3 роки тому

      I think age can be thought of like when he did the year example

    • @nightstarry6350
      @nightstarry6350 3 роки тому

      If you think age in terms of how many years has passed (25-years-old, for example), then it's a discrete variable; If you think age in terms of the exact time, then it's continuous because it can take on any values (1.127287487847 year, for example)

  • @sina4255
    @sina4255 3 роки тому +4

    that moment when u realize the video is mentioning 2016 as a future year

  • @divyashrees1771
    @divyashrees1771 4 роки тому +2

    This was amazing thank you for sharing this

  • @divineestheticsskinhair5497
    @divineestheticsskinhair5497 8 років тому +30

    I like the ant example.

  • @satyam100c
    @satyam100c 4 роки тому

    Thanks alottttt khan academy team for ur selfless service i will always be ur fan ♥️ and sir ur sense of humour is really great I haven't got bored for even a second....now i got to know ki " padhate kaise h"...ie how to really teach someone

  • @mariasaidawi3982
    @mariasaidawi3982 7 років тому +1

    Thanks a lot... I finally understood them.

  • @yourflamingdeath2315
    @yourflamingdeath2315 Рік тому +1

    Thank you once again sensei.

  • @sidharths5147
    @sidharths5147 5 років тому +1

    Adult Blue whale
    Mass:
    50,000 - 150,000 kg
    4:12

  • @rachelkimemia5897
    @rachelkimemia5897 4 роки тому +2

    merci beaucoup Monsieur :)

  • @FatimaAlmamari-g3y
    @FatimaAlmamari-g3y Рік тому

    Thank you for being a better teacher than my professor

  • @hyqhyp
    @hyqhyp 7 років тому

    Because of QM, both exact mass and exact time are discrete. Which begs the question, are there any physical continuous variables? Remember ... as per the title of Hawking's book ... the rest is man's work.

  • @oprabin
    @oprabin 7 років тому +176

    2:36
    bro, you grew up in a zoo?
    XD

  • @reemabdullah9905
    @reemabdullah9905 3 роки тому

    Best Description ever! big like

  • @thewisearchitect
    @thewisearchitect Рік тому

    You have explained a tricky topic in a very easy to understand way. Thank you.

  • @Nadia2Lise
    @Nadia2Lise 11 років тому +3

    Thank you!!!!

  • @stephelton
    @stephelton 4 роки тому

    So... similar to countable vs. uncountable infinity... Discussing real numbers vs. integers might clear this up well for some people.

  • @pyaephyohein7895
    @pyaephyohein7895 2 роки тому

    'This is fun. So keep doing more of these"
    Can't hold my laughter🤣

  • @mishrashubham007
    @mishrashubham007 8 років тому +42

    Great video
    Usain Bolt won though

  • @yayatoure4427
    @yayatoure4427 8 років тому +3

    Thank u so much man, really appreciate it

  • @msoclassychik
    @msoclassychik 8 років тому +57

    lol Yes, Usain won the 100m

  • @saarimshaikh6589
    @saarimshaikh6589 3 роки тому +4

    new orleans '"then you must have known klaus mikaelson"

  • @rholin0997
    @rholin0997 3 роки тому

    I like how the quantization of energy makes it hard to differentiate between discrete and continuous when talking about timing things. @10:10

    • @rholin0997
      @rholin0997 3 роки тому

      These are the thoughts that occur when you finish physical chemistry and then take a stats course...

  • @nishchays
    @nishchays 7 років тому +10

    "We're not talking about random variables that are polite" LOL :P

    • @CanthandleYasir
      @CanthandleYasir 3 роки тому

      @@laiba621 its a special continuos discrete random variable

  • @datsmydab-minecraft-and-mo5666
    @datsmydab-minecraft-and-mo5666 4 роки тому

    Amazing video, it feels like im using a cheat code! whenever i watch these videos, and understand it much better.

  • @kadekevin566
    @kadekevin566 6 років тому +2

    those of you were wondering,an average elephant would weigh 2700-6000 kg depending upon the specie

  • @fernandopellegrini8598
    @fernandopellegrini8598 7 років тому

    I´ve finally understood the difference thanks!

  • @ScilexGuitar
    @ScilexGuitar 7 років тому +1

    He actually predicted the 100 m dash four years in advance :O Thats impressive

  • @XavierXe
    @XavierXe 4 роки тому +3

    His voice have more vibrations than my cellphone
    And its vibrating my ears 👂

  • @zerwinandrepanganiban3869
    @zerwinandrepanganiban3869 6 років тому

    That last example enlightened me. Thanks for this vid

  • @khadeshaalexander7096
    @khadeshaalexander7096 5 років тому

    thank u this made me understand things clearer

  • @brianallen5330
    @brianallen5330 8 років тому +15

    I am by chance watching this video on the night of the 2016 Olympic 100m sprint. I wonder will Sal be right..

    • @LarennPBel
      @LarennPBel 3 роки тому

      I’m here in 2021, Well was he right?

  • @nethrakashyap8729
    @nethrakashyap8729 3 роки тому +1

    You are blessed with a witty sarcasm! 🤣

  • @fishtacosyt8835
    @fishtacosyt8835 2 роки тому

    Really helpful vid! If only my stats teacher was as helpful as you.

  • @alykatequevasz4324
    @alykatequevasz4324 4 роки тому

    This is very helpful. Thanks to this video

  • @mohammedsameer9149
    @mohammedsameer9149 8 років тому +143

    Usain Bolt won though lol

    • @Pilzman3000
      @Pilzman3000 8 років тому +11

      I thought I'd have to look for a while for that comment but here it is right at the top xD

  • @msentence1
    @msentence1 3 роки тому

    Thank you for this. I’m able to understand now. Your explanation and examples helped a lot.

  • @zramsey11
    @zramsey11 Місяць тому

    Hope you can get Douglas Adams to host the followup video on polite random variables.

  • @1nfamyX
    @1nfamyX 10 місяців тому

    2:37 My man grew up in a zoo & still knows way more than us in acamedics 😭

  • @kapamagicman
    @kapamagicman 11 років тому +1

    Perfect sense....thanks!

  • @bendervie
    @bendervie 12 років тому

    Because of Planck's constant, you could say that any mesure in length, masse, time ect is a discrete variable.

  • @cherrymaeremedios9125
    @cherrymaeremedios9125 5 років тому

    thank you so much for your youtube channel Khan Academy.

  • @dulanchathuranga3740
    @dulanchathuranga3740 3 роки тому

    that "100m wining times" example solved my so many life problems at once

  • @internetduck1114
    @internetduck1114 Рік тому

    6:14 timestamp where he contrasts discrete and continuous

  • @binhbietboi
    @binhbietboi 4 роки тому

    Thank you very much.

  • @CrackHeadsLegion
    @CrackHeadsLegion 12 років тому

    I wish I had teachers like you

  • @chuuyang5608
    @chuuyang5608 4 роки тому

    Thank you for this! It helped a lot.