Sampling distribution of the sample mean | Probability and Statistics | Khan Academy

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  • Опубліковано 17 січ 2025
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    The central limit theorem and the sampling distribution of the sample mean
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КОМЕНТАРІ • 114

  • @jiusan
    @jiusan 12 років тому +539

    watching these at 5AM the morning of your statistics midterm at university is the best

  • @peterbryan3971
    @peterbryan3971 6 років тому +83

    You have been saving lives for the last 8 years, Keep doing like this!

  • @enemroy
    @enemroy 8 років тому +59

    Love this Khan guy he breaks it down so well.

  • @vivspring
    @vivspring 13 років тому +15

    thank you :) a slow student like me needs a patient tutor like you. thanks for helping me to understand

  • @applepicker4117
    @applepicker4117 10 років тому +42

    finally, a video about this that makes sense!

    • @JeanPaulUS
      @JeanPaulUS 9 років тому

      Apple Picker I know, right!

  • @elahehnahvi5393
    @elahehnahvi5393 2 роки тому +6

    After 20 years of absence of study, just learning data science asynchronously, your videos are very helpful. thanks

  • @brnjnsvld
    @brnjnsvld 10 років тому +83

    "Skew is where there's few"

    • @elise3617
      @elise3617 4 роки тому

      wow tbh thank you

    • @SimplyAndy
      @SimplyAndy 3 роки тому

      wow now I understand it...

  • @mostinho7
    @mostinho7 2 роки тому +5

    Sampling distribution of the sample mean.
    Sampling distribution: sampled from a probability distribution (that we typically don’t know)
    Sample mean: each sample we take consists of n data points and we take the mean of them.
    We plot all the means of samples we took, each sample with n data points
    Take sample with n data points, find mean of sample, plot it.
    The plot of sample means will be more normal as long as n the number of data points in each sample gets larger, having less skew and kurtosis (measure how normal our distribution is, skew is being shifted left or right and kurtosis is how pointy it is)

  • @midknight198
    @midknight198 4 роки тому +7

    10 years later and it's still relevant and helpful

  • @w.t.h4115
    @w.t.h4115 10 років тому +3

    At 7:25, positive kurtosis should not look like that. it's tail should lower than normal on both side.
    The peak of negative kurtosis should not taller than normal.

  • @a1kiwigirl
    @a1kiwigirl 13 років тому +2

    Thanks, it was nice to have a break from reading, yet not feel guilty about procrastinating.

  • @judyzhu6698
    @judyzhu6698 3 роки тому +2

    Love how enthusiastic you are when teaching us

  • @ankitprasaddevrari4160
    @ankitprasaddevrari4160 7 років тому +19

    drinking game...drink when he says sample

  • @manudewi
    @manudewi 2 роки тому +1

    @Khan Academy can you please clarify for me th following doubt.
    I got confused at 4:11 when you say ."And so when I click animated, what it's going to do is it's going to take FIVE SAMPLES FROM from this probability distribution function..."
    And you keep repeating in the video that it taes 5 samples....
    shouldn't it be." And so when I click animated, what it's going to do is it's going to take ONE SAMPLE OF SIZE FIVE from this probability distribution function..."
    I'd appreciate some help on this. Just thought I understood the topic and then I hear the video's author talking about "taking five samples".

  • @carrd1
    @carrd1 6 років тому +1

    Thank you for all of your videos! They are so helpful!!!!

  • @halima2953
    @halima2953 4 роки тому

    Guess what! You're the best for me so far! Thank you so much

  • @KimSaastamoinen
    @KimSaastamoinen 3 роки тому +2

    Thanks for the video! Might be stupid question but shouldn’t the sample size be noted as ”Sample n” instead of ”Sample N” on the CLT test tool?

  • @AJ-et3vf
    @AJ-et3vf 2 роки тому

    awesome video! THank you!

  • @aishnaarora1336
    @aishnaarora1336 4 роки тому

    you are a blessing Sal Khan!

  • @jinbochen9623
    @jinbochen9623 3 роки тому +1

    2021er here. Thank u

  • @Nughug
    @Nughug 14 років тому +3

    THANK YOU SO MUCH!

  • @cococake0315
    @cococake0315 13 років тому +1

    Thanks!I FINALLY understood!!

  • @sarahaghani2252
    @sarahaghani2252 7 років тому +1

    Thank you so much Sal

  • @tanimowosunkanmi4028
    @tanimowosunkanmi4028 8 місяців тому

    You are amazing!

  • @thatguyadarsh
    @thatguyadarsh 3 роки тому

    so very much informative and intuitive. Thank You

  • @abhayraj3568
    @abhayraj3568 2 роки тому

    So well explained.

  • @rjeption
    @rjeption 2 роки тому +2

    So larger sample sizes would provide more accurate distributions

  • @1337bitcoin
    @1337bitcoin 15 років тому

    Thanks so muchthese are great videos

  • @meriemeennajah7459
    @meriemeennajah7459 Рік тому

    Thank you so much

  • @nanochan1168
    @nanochan1168 8 років тому +1

    Thank you ALOT😭😭..I was completely lost before this video

  • @priyaann9007
    @priyaann9007 4 роки тому

    10 years old yet good video.

  • @Fatcrazypanda
    @Fatcrazypanda 4 роки тому

    Thank you 🙏

  • @rai7323
    @rai7323 Рік тому

    Bravo!

  • @jakeweston5898
    @jakeweston5898 Рік тому

    cheers mr khan

  • @ev1836
    @ev1836 5 років тому

    this guy saves lives

  • @jonathangordon5234
    @jonathangordon5234 8 років тому +2

    How difficult is the proof for the CLT? What level of math is needed to follow it?

    • @davidjohnson-my6sr
      @davidjohnson-my6sr 7 років тому

      Jonathan Gordon literally search it up and judge it for yourself brainlet. with you asking that question, probably more knowledge than you will have within the next 5 years, and our district learnt it in the last year of hs

  • @SinaImani1
    @SinaImani1 14 років тому

    outstanding!

  • @yaboiperson9512
    @yaboiperson9512 3 роки тому +1

    I don't even understand what's going on but nice vid!

  • @Rosie-bi5gz
    @Rosie-bi5gz 6 років тому

    I love khan academy

  • @bakhodiryakubov3981
    @bakhodiryakubov3981 4 роки тому

    does it pick certain number more/less often from the first graph, depending on the probability of the distribution?

  • @harountrabelsi3412
    @harountrabelsi3412 5 років тому +1

    If only my professors were half as good as you

  • @맛있는수박토마토
    @맛있는수박토마토 2 місяці тому

    I am here in 2024 to study the sampling distribution of the sample mean. I came because I thought I was the only one who found it challenging.

  • @sonamnaik2804
    @sonamnaik2804 5 років тому

    ty💙

  • @jimmybro001
    @jimmybro001 13 років тому

    Thanks

  • @corradoblondi9792
    @corradoblondi9792 3 роки тому

    nice

  • @priyak2303
    @priyak2303 5 років тому

    You explain so well😍

  • @iamb2348
    @iamb2348 9 років тому

    For the negative kurtosis example are the tails supposed to reach zero? Shouldnt they go on to infinity like the normal distribution and positive kurtosis?

    • @victor_peral
      @victor_peral 3 роки тому

      Kurtosis is basically concerned about the shape of the peak of the frequency distribution, but ideally a thin tail can lead to a less pointy peak , that tail starts from infinity to infinity

    • @iamb2348
      @iamb2348 3 роки тому

      @@victor_peral Thanks for bringing back my nightmares of university exams :D

    • @victor_peral
      @victor_peral 3 роки тому

      @@iamb2348 can’t believe I replied from 6 years back 🤣😂

  • @raghu_yadav_yt
    @raghu_yadav_yt 10 місяців тому

    👍👍👍

  • @dk.scholar4506
    @dk.scholar4506 8 років тому

    please, can any one tell me how like these videos manufactured ??

  • @rickmonarch4552
    @rickmonarch4552 5 років тому

    But we used here only one random variable. I kinda find it weird. So I guess if it works for one with the given exp.val. and variance then we just add the outputs and still get the normal distribution?

  • @fonty8433
    @fonty8433 Рік тому

    yall gotta get bro a new mic

  • @imranali-iy5wk
    @imranali-iy5wk 7 років тому

    How to make samples in case of without replacement with size 4 can you know any trick please tell me

  • @Lionpolo
    @Lionpolo 8 років тому +5

    Wow
    I literally calculated the area of universe at a particular time by this methodology

    • @ishansrt
      @ishansrt 7 років тому

      how can you do that? the universe is 3d for an average guy who doesn't know relativity

    • @blahbleh5671
      @blahbleh5671 6 років тому +2

      you lying poo

    • @victor_peral
      @victor_peral 3 роки тому

      That’s calculating the area of a sphere , you should get a Nobel price for lies

  • @ramborambo3456
    @ramborambo3456 5 років тому

    can anyone suggest some books

  • @michal234486
    @michal234486 7 років тому +1

    when comparing N=5 and N=25 I think you should look at the ratio kurtosis/sd (or sth like that) to infer about how close to the normal we are (?)

    • @victor_peral
      @victor_peral 3 роки тому

      Perhaps the skew and kurtosis are better indicators for inference , it’s relation to standard deviation might be just for logical purpose I’m guessing

  • @vsimoul
    @vsimoul 15 років тому

    very bice thank you

    • @teluguinfoin
      @teluguinfoin 11 місяців тому

      😮😮you're the first onee

  • @artistiaay5512
    @artistiaay5512 5 років тому

    Whats the difference between median and mean?!

    • @SuperYtc1
      @SuperYtc1 5 років тому +1

      Median is when you got someone called Ian who is medical. Mean is when you are nasty to someone.

  • @yogabagaba93
    @yogabagaba93 12 років тому

    she's so great!

  • @alilalani9531
    @alilalani9531 4 роки тому

    MIDTERM TOMORROW!

  • @victorserras
    @victorserras 7 років тому

    He gets 5 samples and then averages them. What is the size of the original samples? 5 as well?

    • @victor_peral
      @victor_peral 3 роки тому

      The same size is 5 , he just took 5 sampling to illustrate he latter did 1000 sampling of the sample size of 5 and ploted the frequency distribution of mean of each of the 1000 sampling

  • @yogabagaba93
    @yogabagaba93 12 років тому

    nice drawings 7.29

  • @graceyudha
    @graceyudha 4 роки тому

    i think he know everything about everything. he's basically god

  • @mitchellvanvugt8587
    @mitchellvanvugt8587 7 років тому

    sampleception

  • @wolfgangi
    @wolfgangi 6 років тому

    how can God not exist when everything works so beautifully in math and statistics

  • @TimCsbE
    @TimCsbE 12 років тому +1

    KHAAAAAAAAAAAAAAAAAAAAAAAAN

  • @redberries8039
    @redberries8039 7 років тому

    seems to me that a large enough sample size [or the cumulative results of many samples] if plotted would mirror the shape of the original data set ...the values would be different, but the relative frequencies at each position would be the same ...that's right isn't it?

    • @blahbleh5671
      @blahbleh5671 6 років тому

      no

    • @victor_peral
      @victor_peral 3 роки тому

      Not exactly bro , the shape of the sample size will differ from the frequency of mean of samplings taken , we are more concerned that the distribution will look like a normal distribution as the size increase , but the mean of the frequency distribution will be close to the mean of the sample size

  • @palui
    @palui 14 років тому

    It seems to me one needs to be sampling from a non pre-existing, infinite population in order for the CLT to work. For example, the generation of random variables from a population would need to come from something like a rolling of a die where there is no population "size" existing in advance. If the population had a size, like a population of people, then as n approached infinity, it would reach N and the distribution of the means would be a single value. Yes?

  • @dajohnman57
    @dajohnman57 14 років тому +1

    skews are poopy like tails

  • @jessicakraemer2091
    @jessicakraemer2091 4 роки тому

    This frickin class is skewed down👎. I HATE STATISTICS!!!!