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

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Defining discrete and continuous random variables. Working through examples of both discrete and continuous random variables.
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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!
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[@Zhim94]

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

[@abhineelnandi8211]

Entire Video in a single line.

[@notjin2109]

what’s the difference between counting and measuring

[@user-en5gm1vw3c]

@@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]

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]

​@@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]

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]

tell me about it!

[@pradipteeshrestha4097]

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]

no kidding

[@andrewperez8190]

bruh for real..same

[@arianachu9834]

me either

[@mainguy5387]

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]

Excellent, thank you

[@DerrickTay88]

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 !!!

[@feljmusic]

big yes

[@khushigupta5904]

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.

[@pearcei]

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]

us too

[@marijnb4191]

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

[@atiqtajwar1783]

Rebecca Mae me too

[@MookaMG]

I feel you. Having a bad teacher sucks.

[@gunbilegt]

Same here

[@cashele]

"the New Orleans zoo where I grew up" lmaooo

[@khanacademy]

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.

[@killerqueen5624]

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.

[@thinkfeelsolve]

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.

[@shaansinghsingh1113]

live safer thanks gang,

[@AIONBERSERKER]

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

[@mithurajdas225]

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]

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]

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)

[@s_kaukab]

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!

[@Chloe-jz4pr]

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. (:

[@elizaeliza3907]

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

[@thomasip9938]

You are a lot clearer than my teacher!

[@amalnazir8140]

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

[@reeceperry2237]

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

[@andrewzhu5294]

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.

[@yourflamingdeath2315]

Thank you once again sensei.

[@pervertbismarck5067]

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

[@TheIanmurphy]

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

[@thecatman9o9]

u seriously didnt know that??

[@Unknowncuriousity]

​@@thecatman9o9 well he knows now

[@ranaabdullahranaabdullah3296]

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.

[@jonathanlind5725]

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!

[@deborahachor9831]

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]

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

[@SaraAhmed-fp1vi]

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.🤍

[@chinanumberone7723]

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

[@gym5959]

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.

[@PolskaBabii]

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

[@ag6194]

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

[@BasaltMyers]

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

[@nightstarry6350]

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)

[@alfianabdulhalin1873]

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

[@ahlamadel5467]

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

[@Nachiket_upadhye_23]

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

[@HopeAndrea_HFG]

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

[@deathsangel123]

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

[@RB3Vids]

Thank Science

[@sumit121285]

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

[@user-zw3rg2go4o]

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

[@the_growth_mindset.]

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

[@manmohansingh8211]

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

[@skatershawn410]

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

[@nathamha]

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.

[@saarimshaikh6589]

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

[@designhub360customapparel]

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

[@princessmeimban8244]

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

[@elizabethafu8182]

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

[@Mathletelady]

Thank you!

[@VitalySobol]

Please make a lesson about Markov model, about hierarchy of intelligence and how it actually works. It's should be interesting and relevant information.

[@rachelkimemia5897]

merci beaucoup Monsieur :)

[@satyam100c]

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

[@somber087]

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

[@mariachow4353]

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

[@mrjrpnls829]

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

[@stephelton]

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

[@sina4255]

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

[@AlexzandrSpringvale]

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

[@oprabin]

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

[@no_name_magician]

New Orlean's zoo to be exact.

[@thewisearchitect]

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

[@divyashrees1771]

This was amazing thank you for sharing this

[@nishchays]

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

[@CanthandleYasir]

@@laiba621 its a special continuos discrete random variable

[@pinkflower4424]

Thank you khan academy very much 😍😍😍

[@bendervie]

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

[@msoclassychik]

lol Yes, Usain won the 100m

[@mariasaidawi3982]

Thanks a lot... I finally understood them.

[@Nadia2Lise]

Thank you!!!!

[@msentence1]

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

[@FatimaAlmamari-g3y]

Thank you for being a better teacher than my professor

[@XavierXe]

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

[@datsmydab-minecraft-and-mo5666]

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

[@khadeshaalexander7096]

thank u this made me understand things clearer

[@tarunveer5524]

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

[@kadekevin566]

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

[@mayankbhandari3536]

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".

[@andrewvillarreal2152]

so discrete random variable are for things that you can count and continuous random variables are for things you have to measure. But, if you're measuring something and you round it it can turn into a discrete?

[@zerwinandrepanganiban3869]

That last example enlightened me. Thanks for this vid

[@hyqhyp]

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.

[@muhannadalturk7548]

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

[@fernandopellegrini8598]

I´ve finally understood the difference thanks!

[@mishrashubham007]

Great video Usain Bolt won though

[@alykatequevasz4324]

This is very helpful. Thanks to this video

[@fishtacosyt8835]

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

[@yayatoure4427]

Thank u so much man, really appreciate it

[@binhbietboi]

Thank you very much.

[@agpp-24]

Thank you very much. It is very helpful.

[@kapamagicman]

Perfect sense....thanks!

[@thewilloffire4335]

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

[@UsernameHehheh]

Now the exact winning time is also a discrete random value

[@FahadAyon]

Great explanation. Many thanks

[@romeofuertes633]

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

[@brianallen5330]

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

[@LarennPBel]

I’m here in 2021, Well was he right?

[@roseobregon]

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

[@pyaephyohein7895]

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

[@theTeamSlayer353]

explained it soooooo much better than my math teacher

[@RobertoSilva-hj9yn]

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

[@cherrymaeremedios9125]

thank you so much for your youtube channel Khan Academy.

[@rholin0997]

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

[@rholin0997]

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

[@ScilexGuitar]

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

[@CrackHeadsLegion]

I wish I had teachers like you

[@jafarvalishaik9706]

Very Nice explanation on discrete vs continuous variables