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

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  • เผยแพร่เมื่อ 7 ม.ค. 2025

ความคิดเห็น • 406

  • @Zhim94
    @Zhim94 5 ปีที่แล้ว +1253

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

    • @abhineelnandi8211
      @abhineelnandi8211 4 ปีที่แล้ว +130

      Entire Video in a single line.

    • @notjin2109
      @notjin2109 4 ปีที่แล้ว +13

      what’s the difference between counting and measuring

    • @user-en5gm1vw3c
      @user-en5gm1vw3c 4 ปีที่แล้ว +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 ปีที่แล้ว +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 ปีที่แล้ว +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 ปีที่แล้ว +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 ปีที่แล้ว +9

      tell me about it!

    • @pradipteeshrestha4097
      @pradipteeshrestha4097 4 ปีที่แล้ว +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 ปีที่แล้ว +2

      no kidding

    • @andrewperez8190
      @andrewperez8190 4 ปีที่แล้ว +1

      bruh for real..same

    • @arianachu9834
      @arianachu9834 3 ปีที่แล้ว

      me either

  • @mainguy5387
    @mainguy5387 ปีที่แล้ว +96

    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 4 หลายเดือนก่อน +1

      Excellent, thank you

    • @AVPDS99
      @AVPDS99 2 หลายเดือนก่อน +1

      Thank you sooooo much ❤

  • @DerrickTay88
    @DerrickTay88 8 ปีที่แล้ว +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 ปีที่แล้ว +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

    • @billionaireconcepts1095
      @billionaireconcepts1095 7 ปีที่แล้ว

      us too

    • @marijnb4191
      @marijnb4191 7 ปีที่แล้ว +5

      I still kinda struggle with that, maybe you know what thing i dont see

    • @atiqtajwar1783
      @atiqtajwar1783 6 ปีที่แล้ว

      Rebecca Mae me too

    • @MookaMG
      @MookaMG 6 ปีที่แล้ว +5

      I feel you. Having a bad teacher sucks.

    • @gunbilegt
      @gunbilegt 6 ปีที่แล้ว

      Same here

  • @FortniteJoe123
    @FortniteJoe123 2 ปีที่แล้ว +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 หลายเดือนก่อน +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 ปีที่แล้ว +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 ปีที่แล้ว +31

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

  • @cashele
    @cashele 4 ปีที่แล้ว +85

    "the New Orleans zoo where I grew up" lmaooo

  • @thinkfeelsolve
    @thinkfeelsolve 5 ปีที่แล้ว +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.

  • @mithurajdas225
    @mithurajdas225 4 ปีที่แล้ว +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 11 หลายเดือนก่อน

      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.

  • @amalnazir8140
    @amalnazir8140 3 ปีที่แล้ว +11

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

  • @tarunt9153
    @tarunt9153 2 ปีที่แล้ว +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)

  • @Chloe-jz4pr
    @Chloe-jz4pr 4 ปีที่แล้ว +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. (:

  • @Z-eng0
    @Z-eng0 3 ปีที่แล้ว +1

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

  • @andrewzhu5294
    @andrewzhu5294 7 ปีที่แล้ว +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.

  • @thomasip9938
    @thomasip9938 8 ปีที่แล้ว +13

    You are a lot clearer than my teacher!

  • @s_kaukab
    @s_kaukab 3 ปีที่แล้ว +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!

  • @pervertbismarck5067
    @pervertbismarck5067 4 ปีที่แล้ว +49

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

  • @alfianabdulhalin1873
    @alfianabdulhalin1873 8 ปีที่แล้ว +30

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

  • @TheIanmurphy
    @TheIanmurphy 10 ปีที่แล้ว +21

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

    • @thecatman9o9
      @thecatman9o9 3 ปีที่แล้ว

      u seriously didnt know that??

    • @Unknowncuriousity
      @Unknowncuriousity ปีที่แล้ว +2

      ​@@thecatman9o9 well he knows now

  • @skatershawn410
    @skatershawn410 8 ปีที่แล้ว +12

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

  • @mariachow4353
    @mariachow4353 8 ปีที่แล้ว +10

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

  • @jonathanlind5725
    @jonathanlind5725 10 ปีที่แล้ว +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!

  • @HopeAndrea_HFG
    @HopeAndrea_HFG 3 ปีที่แล้ว

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

  • @deborahachor9831
    @deborahachor9831 8 ปีที่แล้ว +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

  • @Nachiket_upadhye_23
    @Nachiket_upadhye_23 4 ปีที่แล้ว +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

  • @sina4255
    @sina4255 3 ปีที่แล้ว +4

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

  • @AlexzandrSpringvale
    @AlexzandrSpringvale 11 ปีที่แล้ว +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.

  • @bibekanandabhattacharjee952
    @bibekanandabhattacharjee952 3 ปีที่แล้ว

    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

  • @princessmeimban8244
    @princessmeimban8244 5 ปีที่แล้ว

    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

  • @somber087
    @somber087 ปีที่แล้ว +1

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

  • @JosephDacula-bx9dm
    @JosephDacula-bx9dm 21 ชั่วโมงที่ผ่านมา

    Best guy ever knowledgeable and have goid sense of humor

  • @chinanumberone7723
    @chinanumberone7723 5 ปีที่แล้ว +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

  • @miyamorgan297
    @miyamorgan297 3 ปีที่แล้ว +1

    Some infinities are bigger than other infinities 7:12

  • @ahlamadel5467
    @ahlamadel5467 5 ปีที่แล้ว +1

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

  • @reeceperry2237
    @reeceperry2237 ปีที่แล้ว

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

  • @saarimshaikh6589
    @saarimshaikh6589 4 ปีที่แล้ว +4

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

  • @elizaeliza3907
    @elizaeliza3907 10 หลายเดือนก่อน

    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

  • @manmohansingh8211
    @manmohansingh8211 5 ปีที่แล้ว +5

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

  • @the_growth_mindset.
    @the_growth_mindset. 5 ปีที่แล้ว

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

  • @elizabethafu8182
    @elizabethafu8182 8 ปีที่แล้ว +2

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

  • @deathsangel123
    @deathsangel123 10 ปีที่แล้ว +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 ปีที่แล้ว

      Thank Science

  • @nishchays
    @nishchays 7 ปีที่แล้ว +10

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

    • @CanthandleYasir
      @CanthandleYasir 3 ปีที่แล้ว

      @@laiba621 its a special continuos discrete random variable

  • @PolskaBabii
    @PolskaBabii 9 หลายเดือนก่อน

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

  • @oprabin
    @oprabin 8 ปีที่แล้ว +176

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

  • @ranaabdullahranaabdullah3296
    @ranaabdullahranaabdullah3296 3 ปีที่แล้ว

    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.

  • @msoclassychik
    @msoclassychik 8 ปีที่แล้ว +57

    lol Yes, Usain won the 100m

  • @vladimirprotein3275
    @vladimirprotein3275 9 หลายเดือนก่อน +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)

    • @mbali.lisikobo
      @mbali.lisikobo 2 หลายเดือนก่อน

      GIRL😭😭😭

  • @sumit121285
    @sumit121285 4 ปีที่แล้ว

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

  • @SaraAhmed-fp1vi
    @SaraAhmed-fp1vi 6 หลายเดือนก่อน

    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.🤍

  • @thewilloffire4335
    @thewilloffire4335 3 ปีที่แล้ว

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

  • @sidharths5147
    @sidharths5147 5 ปีที่แล้ว +1

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

  • @FatimaAlmamari-g3y
    @FatimaAlmamari-g3y ปีที่แล้ว

    Thank you for being a better teacher than my professor

  • @brianallen5330
    @brianallen5330 8 ปีที่แล้ว +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 ปีที่แล้ว

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

  • @reemabdullah9905
    @reemabdullah9905 3 ปีที่แล้ว

    Best Description ever! big like

  • @yourflamingdeath2315
    @yourflamingdeath2315 ปีที่แล้ว +1

    Thank you once again sensei.

  • @mrjrpnls829
    @mrjrpnls829 2 ปีที่แล้ว

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

  • @XavierXe
    @XavierXe 4 ปีที่แล้ว +3

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

  • @mishrashubham007
    @mishrashubham007 8 ปีที่แล้ว +42

    Great video
    Usain Bolt won though

  • @mayankbhandari3536
    @mayankbhandari3536 7 ปีที่แล้ว +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".

  • @rholin0997
    @rholin0997 3 ปีที่แล้ว

    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 ปีที่แล้ว

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

  • @mariasaidawi3982
    @mariasaidawi3982 7 ปีที่แล้ว +1

    Thanks a lot... I finally understood them.

  • @pinkflower4424
    @pinkflower4424 7 ปีที่แล้ว +2

    Thank you khan academy very much 😍😍😍

  • @nathamha
    @nathamha 7 ปีที่แล้ว

    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.

  • @1nfamyX
    @1nfamyX 10 หลายเดือนก่อน

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

  • @kadekevin566
    @kadekevin566 6 ปีที่แล้ว +2

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

  • @ScilexGuitar
    @ScilexGuitar 7 ปีที่แล้ว +1

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

  • @user-zw3rg2go4o
    @user-zw3rg2go4o 8 ปีที่แล้ว +1

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

  • @divineestheticsskinhair5497
    @divineestheticsskinhair5497 8 ปีที่แล้ว +30

    I like the ant example.

  • @nethrakashyap8729
    @nethrakashyap8729 3 ปีที่แล้ว +1

    You are blessed with a witty sarcasm! 🤣

  • @pyaephyohein7895
    @pyaephyohein7895 2 ปีที่แล้ว

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

  • @designhub360customapparel
    @designhub360customapparel ปีที่แล้ว

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

  • @datsmydab-minecraft-and-mo5666
    @datsmydab-minecraft-and-mo5666 4 ปีที่แล้ว

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

  • @fishtacosyt8835
    @fishtacosyt8835 2 ปีที่แล้ว

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

  • @lindielewinski3557
    @lindielewinski3557 6 ปีที่แล้ว

    Had a good laugh when he said "we are not talking about polite random variable" LOL thats funny.

  • @fernandopellegrini8598
    @fernandopellegrini8598 7 ปีที่แล้ว

    I´ve finally understood the difference thanks!

  • @divyashrees1771
    @divyashrees1771 4 ปีที่แล้ว +2

    This was amazing thank you for sharing this

  • @hyqhyp
    @hyqhyp 7 ปีที่แล้ว

    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.

  • @yayatoure4427
    @yayatoure4427 8 ปีที่แล้ว +3

    Thank u so much man, really appreciate it

  • @mohammedsameer9149
    @mohammedsameer9149 8 ปีที่แล้ว +143

    Usain Bolt won though lol

    • @Pilzman3000
      @Pilzman3000 8 ปีที่แล้ว +11

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

  • @theTeamSlayer353
    @theTeamSlayer353 12 ปีที่แล้ว

    explained it soooooo much better than my math teacher

  • @stephelton
    @stephelton 4 ปีที่แล้ว

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

  • @ag6194
    @ag6194 4 ปีที่แล้ว +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 ปีที่แล้ว

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

    • @nightstarry6350
      @nightstarry6350 3 ปีที่แล้ว

      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)

  • @satyam100c
    @satyam100c 4 ปีที่แล้ว

    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

  • @thewisearchitect
    @thewisearchitect ปีที่แล้ว

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

  • @zerwinandrepanganiban3869
    @zerwinandrepanganiban3869 6 ปีที่แล้ว

    That last example enlightened me. Thanks for this vid

  • @internetduck1114
    @internetduck1114 ปีที่แล้ว

    6:14 timestamp where he contrasts discrete and continuous

  • @gym5959
    @gym5959 2 ปีที่แล้ว +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.

  • @msentence1
    @msentence1 3 ปีที่แล้ว

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

  • @rachelkimemia5897
    @rachelkimemia5897 4 ปีที่แล้ว +2

    merci beaucoup Monsieur :)

  • @oren9836
    @oren9836 7 ปีที่แล้ว

    ARIGATO I NEEDED THIS LESSON FOR MY PROJECT

  • @bendervie
    @bendervie 12 ปีที่แล้ว

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

  • @TechnicallyData
    @TechnicallyData 6 ปีที่แล้ว +6

    We ain't talkin about random variables that are polite. Lol

  • @nitaanthpanickar5732
    @nitaanthpanickar5732 หลายเดือนก่อน

    Discrete is Summation, Continuous is Integration

  • @dulanchathuranga3740
    @dulanchathuranga3740 3 ปีที่แล้ว

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

  • @alykatequevasz4324
    @alykatequevasz4324 4 ปีที่แล้ว

    This is very helpful. Thanks to this video

  • @cherrymaeremedios9125
    @cherrymaeremedios9125 5 ปีที่แล้ว

    thank you so much for your youtube channel Khan Academy.

  • @khadeshaalexander7096
    @khadeshaalexander7096 5 ปีที่แล้ว

    thank u this made me understand things clearer