Probability density functions | Probability and Statistics

Probability density functions | Probability and Statistics | Khan Academy

Рет қаралды 2,455,723

15 жыл бұрын

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Probability density functions for continuous random variables.
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Пікірлер: 476

@Quarker 10 жыл бұрын

KhanAcademy: Saving university students who are disgruntled with their inefficient lecturers since 2006.

@riccardocapellino9078 4 жыл бұрын

I had an introduction to statistics for my Physics course, professor spent 1 hour on this and I thought it was complex nonsense..

@amelialane7150 3 жыл бұрын

wait university? I’m in 7th lol and this helps aha

@schjo4635 3 жыл бұрын

@@amelialane7150 keep strong at it you will cary it through till the end of university. I didnt focus well when I was your grade and it cost me

@linalina-tz1tn 3 жыл бұрын

@@riccardocapellino9078 lllllll

@corradoblondi9792 3 жыл бұрын

Man i feel you so badly!

@avananana 2 жыл бұрын

I don't care that this video is over 13 years old, it still contains more useful and comprehensible information than most formal lectures that you can find at universities and colleges. Khan Academy is a blessing to university students.

@SuperOtter Жыл бұрын

yeah but the 240p is kinda annoying

@rishabhpandey12aroll7.5 Жыл бұрын

Sometimes the best content is the vintage one. I still believe that teachers like him are the best teachers that we can find.

@abebayehuhaile49 9 ай бұрын

yeeesssssss

@smartguyray3372 6 ай бұрын

I'm a current student now taking Statistics and although I was looking for something else, this video just helped me understand what I was working on last week and it's clearer now.

@rakhadavin1988 4 ай бұрын

and now was 15 y.o IM watched this video, and still good for me

@aldoralaplume566 9 жыл бұрын

I don't know what people are complaining about. I wasn't born smart, and these videos have saved my life, so thank you so much.

@abhishekbhattacharya7343 8 жыл бұрын

+Aldora LaPlume well said

@mukund1270 8 жыл бұрын

I feel u r ri8

@Thefeared786 7 жыл бұрын

They were probably born after year 2000. That generation doesn't have an attention span unfortunately.

@ghuh1759 6 жыл бұрын

u were born pretty tho, lul.

@lulusaa7499 6 жыл бұрын

Omar Farooqui And you shouldn't label people like this too

@boburnhamsguitar 3 жыл бұрын

its 2021 and im here before my test, Sal you saving me even more than a decade later

@ahmadsherif8624 2 жыл бұрын

same pappy

@Mega88Kat 4 жыл бұрын

this video is so old what why is it still more helpful than my professor

@tanmay1306 3 жыл бұрын

ig your professor is older than that

@ZA-GOAT 3 ай бұрын

15 years ago is crazzyy!! 💀💀

@guitance23 8 жыл бұрын

My tenth video in the Statistics and overall also in Khan academy and I had to now pause it this time and come here to say "Thank You". You explain things very nicely. I like the way you open spaces when you act unsure and also provoke us to think which is good as we get to feel that these notions and certain concepts are just linguistic mappings but the ideas are more than that and they are to be grasped.

@Peter_1986 10 жыл бұрын

Sal started studying math at college and at several universities in his early 20s, and since math tends to be really deep at universities it will give you a great understanding for lots of related subjects. Also, Sal definitely seems to understand how to learn and teach very effectively.

@kaiar 10 жыл бұрын

I feel enlightened! Really much appreciated and I love your sense of humour. passing CFA L 1 seems so much more realistic now!

@Moondye7 12 жыл бұрын

I truely love you

@danielniels22 3 жыл бұрын

love u too

@MrMw3gamer 3 жыл бұрын

Lol wenn man im Masterstudium zum ersten mal statistik hat und dann Moondye unter dem Video sieht XD

@sampurnakc 3 жыл бұрын

Just liked your comment to make the number of likes 69. I also love his explanation though. :)

@jonowilliams3600 7 жыл бұрын

EXACTLY 2 INCHES OF RAIN

@danielniels22 3 жыл бұрын

NOT 2.0000000000000000001 NOT 1.999999999999999999 NOT A SINGLE WATER MOLECULE

@dheerennn 3 жыл бұрын

Is it a .5 chance?

@nocturnalvisionmusic 2 жыл бұрын

@@danielniels22 loved this part too much 🤣

@danielniels22 2 жыл бұрын

@@nocturnalvisionmusic hey thanks for replying my 1 year old comment, it reminds me the day when I first learn stats

@nocturnalvisionmusic 2 жыл бұрын

@@danielniels22 no problem! Good reminder for me too :D

@zukisanimakapela9055 10 жыл бұрын

You are amazing, thanks sir, I'm half way across the world from where you are and your videos are making a huge difference to my learning. Keep it up please...

@rajshah7734 9 ай бұрын

Truly grateful to you, sir! What you explained in just 10 minutes was far better than any of my college or tuition teachers.

@luiscid8937 7 жыл бұрын

Thank you, Khan Academy for allowing me to survive college.

@lisaslavick7737 9 жыл бұрын

OMG I am SO thankful for these videos. I was so lost in my biostatistics class. Thankfully my stepson told me to check them out...lifesaver.

@rishabhpandey12aroll7.5 Жыл бұрын

Sometimes the best content is the vintage one. I still believe that teachers like him are the best teachers that we can find.

@shashankrustagi5611 5 жыл бұрын

10 years of this video, a petal of thanks from INDIA, this helps me in my GATE 2019 exam

@hazelgo952 6 жыл бұрын

Yeah I had my doubts thanks to some of the comments but wow, this was heckin useful thanks man!! I finally understand what that integral is for lol To anyone who says they're wasting 10 minutes, just watch it at a faster speed and skip portions you're already confident in.

@RollerBGM 11 жыл бұрын

Agreed, educators are greatly under-appreciated. This man does more for my education than my professors...

@louiscritchie 10 жыл бұрын

I feel like this should take 1 hour to become a master of, but that is probably just an effect of Khan's explanation.

@tedchirvasiu 5 жыл бұрын

But what's the probability of it being EXACTLY ONE HOUR OF BECOMING?

@jacktheninja 4 жыл бұрын

@@tedchirvasiu basically impossible to master because of that one darn microsecond.

@janetkargbo-fc6uz 9 ай бұрын

There are literal tears forming in my eyes. I’ve been sitting in my probability class feeling so stupid because I couldn’t comprehend this. Thank you so much!!!

@BoZhaoengineering 4 жыл бұрын

this guy is teaching much better than the lecturers in my class. I feel lucky watching the topic centered tutorials.

@erhanfindik2320 2 жыл бұрын

Great explanation so far. Loved this series. Thanks Khan Academy !

@078matthijs 12 жыл бұрын

Around 6:00, when Sal began with doing a bit of Calculus, I smiled. I know Calculus because of the Khan Academy!! I know so much because of the Khan Academy. And it makes me so happy knowing that there are superb lectures out there on which I can rely. Next semester I'm starting with Statistics, unfortunately the teacher is terrible, so thank you Sal for these videos.

@qoxx 2 жыл бұрын

how is life going?

@TheSevenofMine 9 жыл бұрын

Great video! Finally understood PDF. Didn't have a clue during the lecture at university.

@kimikokimi Жыл бұрын

My professor made it sound like something crazy but you just explained it so easily. Thank you!

@p0k_ 7 жыл бұрын

thank you so much, i didn't have a clue how or what these things even were and i have a stats 2 exam in like a month, this video saved my life

@rohitpingale8774 4 жыл бұрын

One of the best stats tutorials, I have ever seen :)

@brendanrivers 11 жыл бұрын

Just the fact that you make these videos changes how I feel about human nature in general. You are a saint!

@caseycdecker 9 жыл бұрын

You should make a video about density function without calculus for uniform continuous variables

@olgadrobina1563 5 жыл бұрын

thanks a lot, your explanations are very to the point, I understand everything

@xmljson9716 4 жыл бұрын

Thank you for your teaching, i totally get the key about the Probability density and PDF.

@thehside 12 жыл бұрын

Thank you so much! Thanks to your vids (which I found through the recommendations on the Stanford online AI Class) I'm finally learning all those things in math that I used to hate so much! You sir probably never will understand this, but just trust me, you are too awesome! ;D

@pinkcray0n 11 жыл бұрын

This is amazing because my prof just told us that given points have no probability but he didn't explain why so I was just memorizing facts but after watching this video I see the logic behind these facts!! Thanks!!

@sithandweyinkosincube2200 5 жыл бұрын

I recommend that these videos are so much useful to my studies.

@Rsingh1 2 жыл бұрын

Thanks! for you understand that we understand things better when presented via graphically

@excelwoman8514 Жыл бұрын

This is really helping, i feel enlightened when i see this. Tysm

@m.fadhiilhaekal7693 3 жыл бұрын

I really enjoyed your videos, thank you for all the Great Work, you really help me with my studies

@carlamk8348 10 жыл бұрын

you save me in every single class!!

@chatsociety 11 жыл бұрын

These videos brought back fears I had in stats classes!

@rishabhnarula1999 10 ай бұрын

wow,sal is such a gem of a teacher,great job.

@apchaphekar 11 жыл бұрын

I agree with the Nobel Prize comment. I think that is the world's most insightful explaination of a normal distribution curve. i feel blessed!

@ashkandv1983 13 жыл бұрын

great and helpful! I should say this is the first or second time that I leave "like " and comment on a video in youtube!!! Ashkan

@MrJamesJ133 9 жыл бұрын

you are so good on explaining maths. thank u so so much for PDF.

@tanmay1306 3 жыл бұрын

Says I don't know upto 10 times in a lecture but knows almost everything that this world has.

@tanmay1306 3 жыл бұрын

@Atharva Kaduskar Nah, Masters' Entrance.

@masonsaldana 7 жыл бұрын

this was great! I understand now that PDF's are continuous functions but just to clarify, in that sense, does that mean that Probability Mass Function (PMF's)/Cumulative Mass Functions (CMF's) are discrete variables that are to only be used if the random variable has an exact number, such as the year a student was born (explained in your continuous/discrete video)?

@zaidhamdaan1905 Жыл бұрын

This video is a blessing for learning this topic Alhamdulillah Thanks sal sir.

@trainedtiger 14 жыл бұрын

I love it! Your incredible! I'm studying for exams to be an actuary, and this is helping me immensely.

@skeletonhorse_person 3 жыл бұрын

TrainedTiger Hey how are you ? You commented this 11 years ago, it’s really interesting to me too see a thought from a person that’s 11 years old, how’s life bud ?

@tasneemahmed3398 10 ай бұрын

@@skeletonhorse_person Heeey! and you commented this 2 years ago, how's life?

@mindbeats-tv 15 жыл бұрын

Thank you so much for sharing and your effort. The explanation is just awesome!!! Great Vid!

@brettwagner2950 7 жыл бұрын

Great video as always. Thanks. But the intuition for the magnitude of the y axis is left dangling. Do we work backwards from a total probability (area) of 1?

@xaladrez7811 Жыл бұрын

I was in Grade 1 when this video came out. Wow. And now im using it

@esmailiyou 6 жыл бұрын

This channel has the best video on probability

@brittothomas8614 10 ай бұрын

wow, just wow.. i am working on learning ML and I am from a non-tech bg, I am at a stage where i wanted to understand what exactly is PDF. I was expecting a vague answer only people mathematically inclined would understand, I was wrong, this make me understand discrete and continuous variables in relation to PDF.. Thank you Khan Academy, now I know here to look for answers that I can understand from ground level

@Calliope1118 14 жыл бұрын

Wow, thank you so much!

@wahaajali1009 4 жыл бұрын

thanks... cleared my concept!

@f.dehchar8194 10 жыл бұрын

That moment at 8:30 when it hits you: "From another persons stand of view this looks like shit - a mess made by a kid - but still far more effective than my book in Prob.&Stat."

@Cube2deth 3 жыл бұрын

I don't understand you

@tharunishadi3980 12 жыл бұрын

you are a life savior !! thanks sal...

@ominous450 12 жыл бұрын

these videos are great. for some reason my prof like to make the material harder than it actually is!

@codeyoga 12 жыл бұрын

Just brilliant ! ThanksSal !

@ngoziekwueme 12 жыл бұрын

Thanks Khan, God bless you!

@andrewpark1471 3 жыл бұрын

I used to watch this back in high school in 2009. Does the resolution gets degraded over time? lol 240p really? Khan Academy saved my life 12 years ago, and now I'm an engineer sitting in my office trying to remember what probability density function was :'D. Guys, you will need this for reliability engineering if you're ever involved in product development! and there Sal saves my life once again after all this time.

@spicytuna08 5 жыл бұрын

i just love your explanation.

@comedifiED 9 жыл бұрын

Helpful as always, thank you.

@danchisholm1 11 жыл бұрын

You rock. I hope you've made lots of money off these. You deserve to.

@sayntfuu 15 жыл бұрын

best channel ever! Thank you!

@_aft 11 жыл бұрын

I like how he starts raging at 4:00 LOLOLO.

@nocturnalvisionmusic 2 жыл бұрын

Me too :D

@oberlinio 2 жыл бұрын

So for variables that cannot be negative, like rain fall, how do we / the function take into consideration that part of the distribution which crosses into negative? Is this where we would use log normal distribution?

@yangjocelyn6959 2 жыл бұрын

Thank you so much for the best explanation.

@NTUDRM 9 жыл бұрын

Very nice explanation. Thanks very much.

@tudor6210 3 жыл бұрын

Thanks, great explanation!

@nelsonw2096 Жыл бұрын

Watching this video in Feb 2023 from San Francisco, and again we are happily watching it rain outside after some rough months leading into this winter. :-)

@zhenminliu 12 жыл бұрын

I find the lecturer very interesting and humorous. Who says Stats has to be boring. Thank you!

@alli4earth 12 жыл бұрын

thank you very much.......... a sweet and short lecture......

@derekedington777 9 жыл бұрын

thank you very helpful

@sharkmentality4554 2 жыл бұрын

Nothing to add, just amazing !!!!

@nocturnalvisionmusic 7 ай бұрын

3:15-4:28 is the best part of the video - love that rain specification 😆😁🌧️

@areeb9781 5 жыл бұрын

Totally a life saviour 🙏

@dobraOsoba 12 жыл бұрын

best explanation i've found yet. why am i not surprised? ;)

@anandw0w 2 жыл бұрын

Omg saving my life thank you!!!!!!!!!!

@dalecomments 7 жыл бұрын

I want to cry.....................great video.....i wished I knew this before....thank you very very much

@Idiosyncratic_flow 3 жыл бұрын

Do you often use Y as the name of the variable on the X-axis in America? I was so confused for the first half of the video. But still so helpful!

@em0vskangoura 12 жыл бұрын

You are more than a GOD of teaching!

@Romeowasbleeding1 14 жыл бұрын

LOL! " Not 2.01 inches of rain. Not 1.99 inches of rain, not 1.99999 inches of rain, not 2000001 inches of rain" Gosh I started to get the feeling that he wasn't going to stop! :D

@nocturnalvisionmusic 2 жыл бұрын

11 years later but same! Loved that part too much 🤣

@nocturnalvisionmusic 7 ай бұрын

I love this still on 12-15-23 😁😇

@Yaki755 Жыл бұрын

its crazy how im 19yo and this vid is here since i was 6, thank you

@kelvinlo0629 10 жыл бұрын

So what does the y-axis of the PDF tell you? What information it would give? or simply ignore it?

@narya211 11 жыл бұрын

great work. thank you

@MrBinitpatel 3 жыл бұрын

Learning from the best teacher in the world..

@srmcarthur 11 жыл бұрын

Let's all tell our educators that they are appreciated today - tell one teacher or a wise helpful person in our life today how we feel. #TeacherAppreciationDay

@imnumber142 12 жыл бұрын

I think this is the first time I have watched one of your videos where you didn't use all the colors in the palette. And I've watched a lot of your videos

@usaf1983 3 жыл бұрын

Your clips are saving my college career

@andrewhunter6880 9 жыл бұрын

Omg the rant about the atoms of rain almost ended me.

@anikakabir9145 4 жыл бұрын

I know right. I was like, I do not have time, just give me the solution.

@nocturnalvisionmusic 2 жыл бұрын

I loved that part honestly 😂

@tusharsalunkhe7916 3 жыл бұрын

really thanks

@ShahariarRabby 7 жыл бұрын

Those who don't understand it, I suggest you to watch the Discrete and continues video. Then you easily get it.

@florgum89 7 жыл бұрын

Why do we need to find the area under the curve? Intuitively I feel that just by averaging out the numbers on the curve (the probabilities) we should get the probability in a range?

@johnnyroc 4 жыл бұрын

The concepts are extremely easy and memorizing all the definitions and formulas is extremely hard. So 50/50 chance I pass my Econometrics class. My professor is useless so I'm all over the web trying to figure it out.