The Expected Value and Variance of Discrete Random Variables

Рет қаралды 351,745

10 жыл бұрын

An introduction to the expected value and variance of discrete random variables. The formulas are introduced, explained, and an example is worked through.
This is an updated and refined version of an earlier video. Those looking for the original version can find it at • Expected Value and Var... .

Пікірлер: 127

@RubenAlvarezMtz 4 жыл бұрын

It is cool to have Khan Academy, 3Blue1Brown and all those content creators but sometimes you just want something straight to the point, thank you JB

@FPrimeHD1618 8 жыл бұрын

Great video man. I'm a math major and find probability 10000000 times more confusing than any course I have taken lol. It doesn't help that our professor only has one tone to his voice, lol. Always nice to have a clear explanation of this material. Thanks!

@jbstatistics 8 жыл бұрын

+FPrimeHD You are very welcome, and thanks for the compliment!

@arkamkhan7691 Жыл бұрын

Lol

@JimbobFaz Жыл бұрын

Ditto.

@boogeythegorilla7330 Жыл бұрын

Months of missing classes and procrastinating before WACE exams has led me up to this point. Thank you so much!!!

@yusuffarah351 4 жыл бұрын

I took so many stat classes at some point even tutor others, but never come a cross some one who can clearly explain this counter intuitive subject. Indeed, knowing a subject and teaching others is too different things. Thank you sir for sharing your knowledge to the world. As some one who love to learn and teach others , I am very grateful to find your videos.

@hellfirelordofevil 7 жыл бұрын

Your exposition of the subject is clear, consise and elegant. Thank you very much for producing this invaluable content!

@jbstatistics 7 жыл бұрын

You are very welcome!

@the_big_al_01 3 жыл бұрын

I'm so lucky to be in your Stats course at Guelph! Best stats prof out there!

@tarehjernetarehjerne4082 Жыл бұрын

Thanks for this amazing video. Clear to the point and very informative. I dont get why lecturers are unable to meet the quality of free KZfaq content

@AmatisoveLove 9 жыл бұрын

Watching one of your videos makes me understand ten times more than reading the textbook, and your content is better than any other statistics-related videos on youtube. Thank you for uploading this and helping me pass my exams!

@jbstatistics 9 жыл бұрын

Złotowłosa Panda You are very welcome. I'm glad you've found my videos helpful!

@jbstatistics 9 жыл бұрын

Złotowłosa Panda You are very welcome. I'm glad you've found my videos helpful!

@poetryflynn3712 Жыл бұрын

Marry me please

@goodknight3072 4 жыл бұрын

Good presentation, likable voice, understandable English, clear explanations, good stuff.

@aria213312 9 жыл бұрын

Thank you sir, you are explaining almost every material that my prof is covering.

@markstephan5492 8 жыл бұрын

Awesome video thanks for posting. I was very confused when my text book showed E(X-E(X))^2 but you explaining that the second E(X) is the mean "μ" was a huge help.

@zaidsada6841 7 жыл бұрын

You have a knack of keeping confusing topics very simple. You got a new subscriber and a fan !

@jonathanm.5066 10 жыл бұрын

Thank you very much for continuing to post statistics videos!

@adrianlindsey2701 3 жыл бұрын

These videos are concise and excellent. Thank you.

@gwineafowl6946 25 күн бұрын

very helpful, even almost 10 years after upload! thanks

@jakeholdroyd193 10 жыл бұрын

Really well put together videos, im refreshing my brain before going back to uni and this is doing the trick nicely, thankyou for making these.

@jbstatistics 10 жыл бұрын

You are very welcome Jake. Thanks for the compliment!

@GoodLuckForever-wi9kb 7 ай бұрын

Best Of Luck Forever For Sharing Such a Deep Knowledge in such a simple way. Well Done Sir

@abdiraheemabi5021 9 жыл бұрын

I rarely take the time to comment let alone like the video, however this video was by far the best I have come across.

@anika_ara9363 8 жыл бұрын

wow!! you were outstanding ya! I understood every part of it but I wish you enlist some related exercises in your website to practice,that would be really helping

@rohanmore1774 5 жыл бұрын

Has somebody ever told you how awesome you are ? If not lemme tell, you sir are great at explaining !!!;)

@ptliang011 9 жыл бұрын

THANK YOU! PLEASE MAKE MORE VIDEOS LIKE THIS ON OTHER SUBJECTS!!! YOU ARE A GOD!

@jbstatistics 9 жыл бұрын

You are very welcome.

@ptliang011 9 жыл бұрын

jbstatistics No seriously, please make more. I saw that you are a stats professor. Can you please make some in this concise format about mathematical statistics? Like show some proofs for these theorems? Can you make some videos on other branches of mathematics like real analysis? Or a video on how to do proofs? Your videos are of higher quality than Khan Academy's. Seriously, this is the clearest explanation of this I have ever seen. Please, please make more videos! Please help us students out. Thank you.

@jackyli1891 9 жыл бұрын

Love your videos you explain everything so well

@jbstatistics 9 жыл бұрын

Thanks Jacky!

@CharinKarashnikov 9 ай бұрын

This video helps me to understand far much better than 3 hours statistics class. Unluckily, found this just only a night before test. 😔

@user-dt7ve8xm7c 4 жыл бұрын

Thank you so much and you explained those concepts very well!!

@lamiahsb6628 9 жыл бұрын

Hi, I would like to thank you a lot for making it possible to me to understand probabilities and I wish that you can make videos about how to solve statistics problems by giving us tips how we can understand well a problem and solve it. and thanks again, your videos are really helpful

@fatimakashefi4312 5 жыл бұрын

worlds of thank you, literally saved my life

@maorazoulay 5 жыл бұрын

finally got it! Book+ professor did such a lousy job explaining this, i'm so grateful!

@jbstatistics 5 жыл бұрын

I'm glad to be of help!

@sushmitanigam4979 7 жыл бұрын

i am grateful to u for providing such an awesome explanation.

@jbstatistics 7 жыл бұрын

Thanks for the kind words!

@souravagarwal5945 8 жыл бұрын

thankyou so much , made my life easy, GOD bless you for helping, keep uploading brother.

@sivakumar-vn7ex 2 жыл бұрын

Bro.I have a doubt ,how did he simulate 1 million values?

@mohashyunis5280 8 жыл бұрын

Thanks so much sir, Very clear understanding.

@jbstatistics 8 жыл бұрын

+Mohash Yunis You are welcome! I'm glad to be of help.

@takeshi0229 4 жыл бұрын

Great video! How did you calculate E(X^2) = 1.92?

@starsaverify 10 ай бұрын

life saviour!! So much better than my nus prof....

@kimberlin6568 6 жыл бұрын

Thank you thank you thank you! It finally clicked for me!

@jbstatistics 6 жыл бұрын

You are very welcome!

@michellerayeonpark7142 5 жыл бұрын

Seriously, you are the BEST

@jbstatistics 5 жыл бұрын

Thanks!

@UrinatingTheCrowd 9 жыл бұрын

Superb. I like your voice, Thanks :D

@DiddyVonDiddy 8 жыл бұрын

Thanks for the incredible videos! I've been using them to study for my exams. Do you cover joint probabilities in any of your videos? I looked for it but maybe it has a different title. thanks again!

@jbstatistics 8 жыл бұрын

+DiddyVonDiddy I don't have anything on joint probability distributions yet. Best of luck on your exams!

@nopecharon Жыл бұрын

your videos are great!!

@ujjwal4065 6 жыл бұрын

Really helpful video . nice video.

@AJ-et3vf 2 жыл бұрын

Awesome video! Thank you!

@jongken3725 9 жыл бұрын

very helpful!much thanks

@zyadalharbi180 5 жыл бұрын

thank you very much. very helpful.

@koketsomokoditoa3255 9 жыл бұрын

thank you- helped a lot

@firefoxyouth 5 жыл бұрын

You Sire deserve an Oscar, although the probability is very low to receive one.. :)

@jbstatistics 5 жыл бұрын

I agree with your probability assessment :)

@KiranAshraf-pf6zt 5 ай бұрын

Nice explanation sir

@a.m2490 4 жыл бұрын

YOU'RE A GOD DAMN HERO

@delta_kh6608 4 жыл бұрын

I just say THANK YOU!!!

@sawaizniaz1034 7 жыл бұрын

Best One😍😍😍😍

@emptyxnes Жыл бұрын

Do you happen to have the link for the video regarding @ 3:50 (handy relationship)? thanks again.

@nm800 5 жыл бұрын

I have two questions: -I read that the variance is how much the data are spread, how much the probability space is filled with different probabilities. Is that right? Does it have to do with dispersion? - Why do we square these values? Why is sigma squared?

@dunethchadeera5838 2 жыл бұрын

Very useful ❤️👍

@AmeerHamza-mt5lm 4 жыл бұрын

Great Sir

@manasviemmadi8072 11 ай бұрын

Does it mean that during calculating relative frequencies and carrying out the experiment, the 60% jaundice/heads is preserved and performed accordingly? Or this can be done only for

@vansikasingh3228 3 жыл бұрын

thank you so much!

@sihlemdziniso3715 2 жыл бұрын

your videos are easy to understand but please include all the calculation

@pitbullman925 2 жыл бұрын

thank you so much ..

@sohail2318 7 жыл бұрын

excuse me sir, do we calculate expectation for given range of random variable asked or we calculate for all the possible out comes? for instance if we are asked to find p(2

@aizeckmwangonda4829 5 жыл бұрын

Sorry how can get P(x)

@seemaalsaidy6093 4 жыл бұрын

Thank you.

@spencerprice1676 5 жыл бұрын

Love these videos, can you explain why you might want to square x @7:43

@yangxiang9933 5 жыл бұрын

since it might be useful to use when finding variance (var=E(x^2)-E(x)^2)

@abercrombie4ever100 4 жыл бұрын

THANK YOU!

@Ali-Ezzat 4 жыл бұрын

On man I don't know what to say Thanks so much Oh BTW where can I find a good illustration for relative frequencies?

@romanrobinson1860 2 жыл бұрын

At 4:27, the example to be worked out is different from the explanation given after. I am not so sure why. Can this be resolved?

@rfconnor3887 6 жыл бұрын

Where could I find the proof the relationship at 4:22?

@sfaabz 4 жыл бұрын

kzfaq.info/get/bejne/nbyGrLOr28Csc2g.html

@sim5099 5 жыл бұрын

Thank you!!

@jbstatistics 5 жыл бұрын

You are very welcome!

@spectator5144 2 жыл бұрын

6:58 what would be the R code to generate this simulation? thank you

@ajshaka3212 5 ай бұрын

Awesome vid

@jbstatistics 5 ай бұрын

Thanks!

@muratderekoylu4673 7 жыл бұрын

thank you sir

@jbstatistics 7 жыл бұрын

You are very welcome.

@ahmalkadumas4539 Ай бұрын

amazing

@mdsamiuzzamanreal3504 5 жыл бұрын

sir thanks

@parthi2929 6 жыл бұрын

2:10 But why that multiplication? You could have given the background there.

@bhargabsaharia6361 6 жыл бұрын

very helpfull

@jbstatistics 6 жыл бұрын

Thanks!

@lluismontalat4040 3 жыл бұрын

legend

@halimahabdulbaki5149 6 жыл бұрын

hello, pls can someone help me out with how p(x) was found.

@normanremedios8190 2 жыл бұрын

Almost perfect, if not perfect.

@koby9340 3 жыл бұрын

One question please I don't get it why segma squared is equal to expected value shouldn't it be segma squared equal expected value divided by N the number of element in a population

@841533356v 7 жыл бұрын

wow nice

@jbstatistics 7 жыл бұрын

Thanks!

@estherowusu-ameyaw7781 2 жыл бұрын

Please I had 1.92 for the expected value. Can anyone please show me where I went wrong?

@nurulnabilah6941 5 жыл бұрын

🎉

@rahulpatil6568 5 жыл бұрын

1) E(X^2) is greatherthan equal to (E(X))^2 or 2) E(X^2) only greatherthan (E(X))^2 i m confused.... which one is RIGHT...

@jbstatistics 5 жыл бұрын

E(X^2) = (E(X))^2 if and only if Var(X) = 0. Var(X) is only 0 for a degenerate distribution, where X can only be a specific constant. In any distribution where there is any variability at all, E(X^2) > (E(X))^2.

@alex-my8hp 4 жыл бұрын

god damn your good!

@aizeckmwangonda4829 5 жыл бұрын

How can get P(x)

@ravidwivedi6648 5 жыл бұрын

Records show that 30o/o of all patient9 admitted to a medical clinic fail to pay their dues and eventually their bills are forgiven. Suppose four patients represent a random selection from the large set of prospective patients served by the clinic. Find the probabiliry rhat ; (, all patient's bills wilt evenrually be forgiven (ii) at least one patient bill will be forgiven. Is there anyone who can make me understand what the method to solve this. Help Will Be Needful. TIA

@bleepbloop7768 2 жыл бұрын

why is the p of 1 child having NJ or JN = 0.48 ? wouldn't it be 0.096?

@tawseeftaher9109 Жыл бұрын

math 4:26

@thecoolgamer4842 Жыл бұрын

You make me wanna cry ur voice is so mono toned

@MohammedAB2030 4 жыл бұрын

The English language is so confusing

@kevinloones5395 5 жыл бұрын

@shrimatkapoor2200 6 жыл бұрын

Is this guy from Khan Academy Physics cuz he sounds like the same guy

@jbstatistics 6 жыл бұрын

Nope. I've never been associated with the Khan Academy in any way.

@OfficialTurkz 6 жыл бұрын

nadugo utak ko

@mkosiba79 8 жыл бұрын

Say that again...

@someoneunknownnn 2 ай бұрын

Ye oswal ki book yahan kyu le aaya 😭

@farouk5344 3 жыл бұрын

Exam is tomorrow, wish me luck ?

@jbstatistics 3 жыл бұрын

Best of luck!

@raghad6024 Жыл бұрын

bro u deserve my house not just a like

@anika_ara9363 8 жыл бұрын

wow!! you were outstanding ya! I understood every part of it but I wish you enlist some related exercises in your website to practice,that would be really helping

@anika_ara9363 8 жыл бұрын

wow!! you were outstanding ya! I understood every part of it but I wish you enlist some related exercises in your website to practice,that would be really helping

@jbstatistics 8 жыл бұрын

+Anika_Ara Thanks Anika, and thanks for the suggestion. I have many exercises with full solutions that I intend to post at some point in the not-too-distant future. All the best!

@anika_ara9363 8 жыл бұрын

okay waiting for that :-D