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

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  • Опубліковано 5 гру 2012
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    Defining discrete and continuous random variables. Working through examples of both discrete and continuous random variables.
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КОМЕНТАРІ • 392

  • @Zhim94
    @Zhim94 4 роки тому +1063

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

    • @abhineelnandi8211
      @abhineelnandi8211 3 роки тому +115

      Entire Video in a single line.

    • @notjin2109
      @notjin2109 3 роки тому +12

      what’s the difference between counting and measuring

    • @user-en5gm1vw3c
      @user-en5gm1vw3c 3 роки тому +53

      @@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 3 роки тому +7

      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 3 роки тому +31

      ​@@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 3 роки тому +667

    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 3 роки тому +9

      tell me about it!

    • @pradipteeshrestha4097
      @pradipteeshrestha4097 3 роки тому +19

      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 3 роки тому +2

      no kidding

    • @andrewperez8190
      @andrewperez8190 3 роки тому +1

      bruh for real..same

    • @arianachu9834
      @arianachu9834 3 роки тому

      me either

  • @mainguy5387
    @mainguy5387 8 місяців тому +21

    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."

  • @DerrickTay88
    @DerrickTay88 8 років тому +246

    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 9 років тому +472

    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

  • @khushigupta5904
    @khushigupta5904 4 місяці тому +6

    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.

  • @killerqueen5624
    @killerqueen5624 Рік тому +9

    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.

  • @cashele
    @cashele 3 роки тому +76

    "the New Orleans zoo where I grew up" lmaooo

  • @pervertbismarck5067
    @pervertbismarck5067 3 роки тому +47

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

  • @khanacademy
    @khanacademy  11 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 8 років тому +33

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

  • @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!

  • @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!

  • @thinkfeelsolve
    @thinkfeelsolve 4 роки тому +30

    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.

  • @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. (:

  • @deborahachor9831
    @deborahachor9831 7 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

  • @PolskaBabii
    @PolskaBabii 2 місяці тому

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

  • @roseobregon
    @roseobregon 5 років тому

    Thanks for the great examples! It cleared up a lot of confusion!

  • @msentence1
    @msentence1 2 роки тому

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

  • @amalnazir8140
    @amalnazir8140 3 роки тому +9

    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 +29

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

  • @reeceperry2237
    @reeceperry2237 11 місяців тому

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

  • @tarunt9153
    @tarunt9153 Рік тому +6

    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)

  • @muhannadalturk7548
    @muhannadalturk7548 4 роки тому

    very clear explanation. I find your channel to be extremely helpful!

  • @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 4 місяці 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.

  • @thomasip9938
    @thomasip9938 7 років тому +13

    You are a lot clearer than my teacher!

  • @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

  • @sumit121285
    @sumit121285 3 роки тому

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

  • @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

  • @elizabethafu8182
    @elizabethafu8182 7 років тому +2

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

  • @yayatoure4427
    @yayatoure4427 7 років тому +3

    Thank u so much man, really appreciate it

  • @zerwinandrepanganiban3869
    @zerwinandrepanganiban3869 5 років тому

    That last example enlightened me. Thanks for this vid

  • @chuuyang5608
    @chuuyang5608 4 роки тому

    Thank you for this! It helped a lot.

  • @TamiProvost
    @TamiProvost 7 років тому

    Great lesson and visuals! Thanks so much! :)

  • @elizaeliza3907
    @elizaeliza3907 3 місяці 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

  • @fernandopellegrini8598
    @fernandopellegrini8598 7 років тому

    I´ve finally understood the difference thanks!

  • @the_growth_mindset.
    @the_growth_mindset. 5 років тому

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

  • @hinekanter1150
    @hinekanter1150 9 років тому

    This was so helpful! Thanks you

  • @thewisearchitect
    @thewisearchitect Рік тому

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

  • @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!

  • @mariasaidawi3982
    @mariasaidawi3982 7 років тому +1

    Thanks a lot... I finally understood them.

  • @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

  • @skatershawn410
    @skatershawn410 7 років тому +12

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

  • @andrewzhu5294
    @andrewzhu5294 6 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.

  • @sina4255
    @sina4255 2 роки тому +4

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

  • @lifelover9989
    @lifelover9989 5 років тому

    This helped me a lot 😊
    God bless you🙏

  • @user-zw3rg2go4o
    @user-zw3rg2go4o 7 років тому +1

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

  • @RobertoSilva-hj9yn
    @RobertoSilva-hj9yn 4 роки тому

    Thank you very much, it was a very clear and helpful explanation

  • @ranaabdullahranaabdullah3296
    @ranaabdullahranaabdullah3296 2 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.

  • @fishtacosyt8835
    @fishtacosyt8835 Рік тому

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

  • @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.

  • @divyashrees1771
    @divyashrees1771 4 роки тому +2

    This was amazing thank you for sharing this

  • @khadeshaalexander7096
    @khadeshaalexander7096 4 роки тому

    thank u this made me understand things clearer

  • @ahlamadel5467
    @ahlamadel5467 5 років тому +1

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

  • @TheIanmurphy
    @TheIanmurphy 9 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!

    • @thecatman9o9
      @thecatman9o9 2 роки тому

      u seriously didnt know that??

    • @skies1437
      @skies1437 Рік тому +2

      ​@@thecatman9o9 well he knows now

  • @SmazzitSEOTrainingInstitute
    @SmazzitSEOTrainingInstitute 10 місяців тому

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

  • @kapamagicman
    @kapamagicman 10 років тому +1

    Perfect sense....thanks!

  • @mrjrpnls829
    @mrjrpnls829 2 роки тому

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

  • @satyam100c
    @satyam100c 3 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

  • @alykatequevasz4324
    @alykatequevasz4324 3 роки тому

    This is very helpful. Thanks to this video

  • @mariachow4353
    @mariachow4353 8 років тому +9

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

  • @ms.angelicapagdilao6037
    @ms.angelicapagdilao6037 2 роки тому

    Thank you very much. It is very helpful.

  • @nathamha
    @nathamha 6 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.

  • @tarunveer5524
    @tarunveer5524 2 роки тому

    Thanks Sir. This really Helped me a lot.......

  • @chinanumberone7723
    @chinanumberone7723 4 роки 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

  • @FahadAyon
    @FahadAyon 2 роки тому

    Great explanation. Many thanks

  • @romeofuertes633
    @romeofuertes633 6 років тому

    thanks your a big help i hope you have input some test on your video

  • @user-ho9ni1hd6s
    @user-ho9ni1hd6s Рік тому

    Thank you for being a better teacher than my professor

  • @MrDoraemon2100
    @MrDoraemon2100 11 років тому

    Superb ! Great video as always.Keep up your good works.

  • @TheLezhenkin
    @TheLezhenkin 11 років тому

    This is exactly what I did in my AP Stats class yesterday.

  • @whattheydoexactly7794
    @whattheydoexactly7794 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

  • @CrackHeadsLegion
    @CrackHeadsLegion 11 років тому

    I wish I had teachers like you

  • @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".

  • @pinkflower4424
    @pinkflower4424 7 років тому +2

    Thank you khan academy very much 😍😍😍

  • @AlexzandrSpringvale
    @AlexzandrSpringvale 10 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.

  • @jafarvalishaik9706
    @jafarvalishaik9706 5 років тому

    Very Nice explanation on discrete vs continuous variables

  • @somber087
    @somber087 Рік тому +1

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

  • @msoclassychik
    @msoclassychik 7 років тому +58

    lol Yes, Usain won the 100m

  • @lindielewinski3557
    @lindielewinski3557 6 років тому

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

  • @doreeen7697
    @doreeen7697 3 роки тому

    This is video that we can learn easily about random V😊

  • @yourflamingdeath2315
    @yourflamingdeath2315 7 місяців тому +1

    Thank you once again sensei.

  • @rachelkimemia5897
    @rachelkimemia5897 4 роки тому +2

    merci beaucoup Monsieur :)

  • @caojing6256
    @caojing6256 4 роки тому

    Very helpful, thanks

  • @Nadia2Lise
    @Nadia2Lise 10 років тому +3

    Thank you!!!!

  • @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.

  • @romeiyu3491
    @romeiyu3491 Місяць тому

    thank you so much for this

  • @cherrymaeremedios9125
    @cherrymaeremedios9125 4 роки тому

    thank you so much for your youtube channel Khan Academy.

  • @stephelton
    @stephelton 3 роки тому

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

  • @pyaephyohein7895
    @pyaephyohein7895 Рік тому

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

  • @reemabdullah9905
    @reemabdullah9905 2 роки тому

    Best Description ever! big like

  • @nishchays
    @nishchays 7 років тому +10

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

    • @CanthandleYasir
      @CanthandleYasir 2 роки тому

      @@laiba621 its a special continuos discrete random variable

  • @lekhayes13
    @lekhayes13 5 років тому

    Excellent video!!

  • @fayolamaulida1663
    @fayolamaulida1663 3 роки тому

    Thank you so much!

  • @manmohansingh8211
    @manmohansingh8211 5 років тому +5

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

  • @oren9836
    @oren9836 6 років тому

    ARIGATO I NEEDED THIS LESSON FOR MY PROJECT

  • @bendervie
    @bendervie 11 років тому

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

  • @binhbietboi
    @binhbietboi 4 роки тому

    Thank you very much.

  • @user-ep8lb5tf6l
    @user-ep8lb5tf6l 4 місяці тому

    Thanks for this i know how to now

  • @GAment_11
    @GAment_11 3 роки тому

    You make learning fun.

  • @Physics_with_Muscles
    @Physics_with_Muscles 2 роки тому +1

    Thank you!