Probability density functions | Probability and Statistics | Khan Academy
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- Опубліковано 14 лют 2009
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Probability density functions for 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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KhanAcademy: Saving university students who are disgruntled with their inefficient lecturers since 2006.
I had an introduction to statistics for my Physics course, professor spent 1 hour on this and I thought it was complex nonsense..
wait university? I’m in 7th lol and this helps aha
@@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
@@riccardocapellino9078 lllllll
Man i feel you so badly!
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.
yeah but the 240p is kinda annoying
Sometimes the best content is the vintage one. I still believe that teachers like him are the best teachers that we can find.
yeeesssssss
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.
and now was 15 y.o IM watched this video, and still good for me
15 years ago is crazzyy!! 💀💀
its 2021 and im here before my test, Sal you saving me even more than a decade later
same pappy
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.
+Aldora LaPlume well said
I feel u r ri8
They were probably born after year 2000. That generation doesn't have an attention span unfortunately.
u were born pretty tho, lul.
Omar Farooqui And you shouldn't label people like this too
this video is so old what
why is it still more helpful than my professor
ig your professor is older than that
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.
EXACTLY 2 INCHES OF RAIN
NOT 2.0000000000000000001
NOT 1.999999999999999999
NOT A SINGLE WATER MOLECULE
Is it a .5 chance?
@@danielniels22 loved this part too much 🤣
@@nocturnalvisionmusic hey thanks for replying my 1 year old comment, it reminds me the day when I first learn stats
@@danielniels22 no problem! Good reminder for me too :D
I feel enlightened! Really much appreciated and I love your sense of humour. passing CFA L 1 seems so much more realistic now!
I truely love you
love u too
Lol wenn man im Masterstudium zum ersten mal statistik hat und dann Moondye unter dem Video sieht XD
Just liked your comment to make the number of likes 69. I also love his explanation though. :)
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.
Thank you, Khan Academy for allowing me to survive college.
Truly grateful to you, sir! What you explained in just 10 minutes was far better than any of my college or tuition teachers.
Sometimes the best content is the vintage one. I still believe that teachers like him are the best teachers that we can find.
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...
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.
Agreed, educators are greatly under-appreciated.
This man does more for my education than my professors...
10 years of this video, a petal of thanks from INDIA, this helps me in my GATE 2019 exam
Just the fact that you make these videos changes how I feel about human nature in general. You are a saint!
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!!!
this guy is teaching much better than the lecturers in my class. I feel lucky watching the topic centered tutorials.
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.
how is life going?
you save me in every single class!!
I feel like this should take 1 hour to become a master of, but that is probably just an effect of Khan's explanation.
But what's the probability of it being EXACTLY ONE HOUR OF BECOMING?
@@tedchirvasiu basically impossible to master because of that one darn microsecond.
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.
My professor made it sound like something crazy but you just explained it so easily. Thank you!
Says I don't know upto 10 times in a lecture but knows almost everything that this world has.
@Atharva Kaduskar Nah, Masters' Entrance.
One of the best stats tutorials, I have ever seen :)
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!
These videos brought back fears I had in stats classes!
You should make a video about density function without calculus for uniform continuous variables
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.
wow,sal is such a gem of a teacher,great job.
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!!
Great explanation so far. Loved this series. Thanks Khan Academy !
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
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. :-)
I love it! Your incredible! I'm studying for exams to be an actuary, and this is helping me immensely.
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 ?
@@skeletonhorse_person Heeey! and you commented this 2 years ago, how's life?
I was in Grade 1 when this video came out. Wow. And now im using it
Great video! Finally understood PDF. Didn't have a clue during the lecture at university.
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
I recommend that these videos are so much useful to my studies.
3:15-4:28 is the best part of the video - love that rain specification 😆😁🌧️
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
This channel has the best video on probability
thanks a lot, your explanations are very to the point, I understand everything
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
Thank you for your teaching, i totally get the key about the Probability density and PDF.
I find the lecturer very interesting and humorous. Who says Stats has to be boring. Thank you!
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
these videos are great. for some reason my prof like to make the material harder than it actually is!
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)?
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
11 years later but same! Loved that part too much 🤣
I love this still on 12-15-23 😁😇
This is really helping, i feel enlightened when i see this. Tysm
you are a life savior !! thanks sal...
Thanks! for you understand that we understand things better when presented via graphically
You are more than a GOD of teaching!
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."
I don't understand you
you are so good on explaining maths. thank u so so much for PDF.
Those who don't understand it, I suggest you to watch the Discrete and continues video. Then you easily get it.
This guy is crazy, There is no one like Sal Khan my god !
Just brilliant ! ThanksSal !
thanks... cleared my concept!
Learning from the best teacher in the world..
I really enjoyed your videos, thank you for all the Great Work, you really help me with my studies
You rock. I hope you've made lots of money off these. You deserve to.
Khan Academy still outchea saving lives and degrees!
This video is a blessing for learning this topic
Alhamdulillah
Thanks sal sir.
its crazy how im 19yo and this vid is here since i was 6, thank you
Wow, thank you so much!
Thank you so much for sharing and your effort.
The explanation is just awesome!!!
Great Vid!
I like how he starts raging at 4:00 LOLOLO.
Me too :D
Thanks Khan, God bless you!
15 years later ma guy still be helping me out.
best channel ever! Thank you!
i just love your explanation.
Totally a life saviour 🙏
Nothing to add, just amazing !!!!
you are awesome
made me grasp this concept better then any of my previous classes
Are you alive now?
Omg saving my life thank you!!!!!!!!!!
Helpful as always, thank you.
Thank you so much for the best explanation.
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
Your clips are saving my college career
Thanks, great explanation!
Wonderful insights.
One point nein, nein, nein, nein, nein!
+Rasmus Karlsson Irritated me as well.
my dirty mind
@@mr.premponvilai9983 don't we all have those :3
Very nice explanation. Thanks very much.
Extremely well explained
The response you got from Cy Fleming was correct. If you think about it logically with the rain example then, what would it mean if the distribution graph was peaking at 0,9 (y-axis) at 3 inches of rain (x-axis) while considering that the total area under the graph must equal to 1? Naturally it would mean a higher probability of getting *about* 3 inches of rain when compared to say 2 or 4 inches. Thus, the height represents how widely or narrowly the potential values of Y (rain) are distributed.
I want to cry.....................great video.....i wished I knew this before....thank you very very much
thank you very helpful
best explanation i've found yet. why am i not surprised? ;)
This video should be named as 'continuous random variables' instead of 'probability density functions'. Probability density functions are one of two ways to describe the distribution of continuous random variables; and they're the derivatives of cumulative distribution functions.
really thanks
He just cleared my basic doubt and helped me what actually continuous means
@Cerpin1 Basically any distribution showing you the prob. of a given value of a random variable is a prob. distribution. When we talk about discrete random variables it's called prob. mass function, and when continuous it's called prob. density function.
btw, I love these videos, great explanation!
No doubt after internet came .. suddenly science got advanced.. cuz now students can understand what someone tryna teach in lectures
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?
thank you very much.......... a sweet and short lecture......