Range, variance and standard deviation as measures of dispersion | Khan Academy
Вставка
- Опубліковано 30 вер 2024
- Courses on Khan Academy are always 100% free. Start practicing-and saving your progress-now: www.khanacadem...
Practice this lesson yourself on KhanAcademy.org right now:
www.khanacadem...
Watch the next lesson: www.khanacadem...
Missed the previous lesson?
www.khanacadem...
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!
About Khan Academy: Khan Academy offers practice exercises, instructional videos, and a personalized learning dashboard that empower learners to study at their own pace in and outside of the classroom. We tackle math, science, computer programming, history, art history, economics, and more. Our math missions guide learners from kindergarten to calculus using state-of-the-art, adaptive technology that identifies strengths and learning gaps. We've also partnered with institutions like NASA, The Museum of Modern Art, The California Academy of Sciences, and MIT to offer specialized content.
For free. For everyone. Forever. #YouCanLearnAnything
Subscribe to KhanAcademy’s Probability and Statistics channel:
/ @khanacademyprobabilit...
Subscribe to KhanAcademy: www.youtube.co...
And here i am, 10 years after this was posted, learning more here in 12 min than my course in an hour
Thank u from the heart of mine, khan academy !
I played this at 2x speed to learn it in 6 min
Same lo
@@vincentdrew2194 That’s not smart, you might not understand everything because your brain can’t catch up. Don’t try to get everything done as quick as possible, sometimes it causes mistakes
reviewing simple explanation after hours of complicated lesson often give you a new understanding and you feel enlightenment.
There am I scrolling down and liking every comment coz I can relate to them
Seeing how you have 142 likes....... I wonder
i cried cos this helped me so much
did it sound something like trololollololololoololollololol
***** Right? Isn't Khan amazing? Khan Academy makes me realize that math isn't so bad when explained properly. So many teachers and books explains things in a cryptic manner. Khan explains this stuff in layman's terms and it just clicks.
Did you pee yourself too?
Same!!! In class I was like what is this even and here I understood it 😂🌸🌸
JJ not math, its statistics.
Oh my god yes. Not all superheroes wear capes
Plot twist: he was wearing a cape
@@lkerzgrl24 Plot twist. OP is talking about Iron Man.
@@whitewalker608plot twist he is talking about Superman 😂
Plot twist. The entire plot has become twisted.
I am taking a Statistics class online and YOU are by far the BEST thing I've come across! Your explanations are clear and thorough. You cut through all the STATISTIC jargon and allow the student to conceptualize the theory of basic statistical analyses & problems. You are truly Gifted!Thank you for sharing your knowledge and Passion.
right! thats facts! my statistics professor talks so confusing and quickly! I had no choice but to find other videos to study for our weekly concepts! I couldnt go out like that!
Everyone is talking about their professors in university and how they're useless like 7-2 years ago I'm here in 2020 trying to figure this out in high school because I hate remote learning.
that sounds very difficult dear, i can't even imagine having to do high school right now. i'm sorry you have to go through that
same
me too
@@Lillith9008 thank u for being compassionate
This made so much more sense than my university professor. Thanks a lot!
great work but #are so small and the board is so dark?
Harijs Ijabs why are you learning this in university? I'm learning this in the 6th grade
bcuz we all have specific concepts we are learning in college such as criminal justice or law or engineering. But there are a few courses that you have to repeat that u've already learned in middle and highschool. Thats why kid.
+FloydFilmz why'd we pay thousands to repeat what we've already learned?
@@azimtwice idk
I have studied these concepts in at least three different classes and never understood them as well as I do now. Thank you.
Learned more with this video than the first 3 weeks of college with my useless professor
Hold on you r learning this in Uni then why am i learning this year 9 or 9th grade
AUstralia IS messed up
College?
We're learning this in grade 9 though
@@herat3158 thats what i said but in australia we call college uni
I’m learning this in 7th
@@lily-er5xt yeah, same.
I need Sal to take my SAT for me.
I thought it was n-1?
Exactly
This guy has done so much on Khan Academy, he should be nominated for the Nobel Prize in Education. If there isn't such a category, they should create one
Amazing teaching skills, i've struggled to understand this in university for the past 2 months, with my prof being of little use. first time watching this 10min video and i completely understand it now! Thank you!
just goes to show these universities are so overrated. they don't teach anymore. About to graduate myself and it is so funny what university teaching has become.
Khan academy... helped my 14 year old self, and still helping me at 24 years old, God bless you.
Very well explained. However, I find another explanation stating that the denominator in variance calculation should be n-1, which in this case should be 4 (5-1=4). Please clarify. Thanks
+Saul Matakarawa I believe n-1 is to calculate the sample variance.
Not 100% sure, but from what I remember.
somebody else explained please
vortex.ihrc.fiu.edu/MET4570/members/Lectures/Lect05/m10divideby_nminus1.pdf
Check page 2
Sample Variance’s denominator is n-1. Population variance’s is n
@@pppkaew4297 thanks
Please never delete your videos. I am also 10 years after posting learning this stuff and you are the only one who explained it the way i could understand and use it. Youe helped, help and will help millions of people. Thank you
Bro why am I learning this in year 7 💀
Simply , Its Great . Thank you
Your method of teaching is comprehensible, thanks
You know Mr. Khan, you and you alone are the reason this program works so well. What you teach is no different than a university professor, but the way you teach it squeezes more information into a 12 minute video than I'll get in a 50 minute lecture, and I understand it much better. I think I speak for everyone when I say I wish you were my teacher, you'd be absolutely perfect at it.
How come he is dividing with 5 and not with 5-1? In my textbook it says that the variance s^2 is the SUM of (xi - mean)^2 divided by n-1. You are only dividing by n and not by n-1. How come?
Thank you u explained it so seamlessly 😭👏🏽. U save me from failing a test
13 years later, yup learning from here more than my professors
a video explaining sample variance and population variance would be helpful.. (my synapses are shutting down)
Khan, you legend. Needed a quick primer on this topic. You are the man.
Thank you so much for this!!!! ♥️ You’re a blessing! ♥️🙌🏼
Background should be white. Yellow text on black BG is hard to focus on
This video was made 12years ago
For the square root of 200 I get 14.142... How am I understanding this wrong... Great video. You are a really good explainer.
Awesome video and great explanation. But one quick correction, 9:48 Distance can't be negative or zero.
These people are in college learning this while I'm still in middle school learning thus during social distancing
@Yash Verma I wasn't trying to be
Why are you mad?
Thaaanx
Is it just me or does he sound like old Ted Mosby? Great video btw, I've been watching them before class and they are super helpful!
in the variance section isn't it divided by 4 not 5 , like the formula is 1/n-1
? I am confused
Is there a mistake?? All other videos say you divide by n-1 for variance.
Very useful
And I have a ÇA tomorrow big help🙏🏽
Find the variance of "94,94,92,94,96,97"
Tell me
Ik the answer
Why did you divide by 5 instead of 4 ! I know that you have to divide by the number of data but in the standard deviation you have to subtract 1 from the number of data, so it should be 4 not 5 !? could someone explain ?
Ohh I just figured out that you calculated the standard deviation for a population not for a sample !!
now it makes a lot of sense to me
thanks !
What is the standard? Population or the Sample?
he calculates population standard deviation
did you ever find the answer? cause i was thinking the same. thanks
population is when you have all the data that you need, thus only dividing by n, when you only have a sample of the data, you divide n-1
Thank you. You are really good explaining !!
why is it the denominator not n-1 in getting the variance?
Lenefer Cuico because it’s dealing with population, if it were a sample example then you would do n-1 instead. :)
Thanks so much (from Southern hemisphere)!
Variance....Ghlat find kiya hai:-P
You write neater with that mouse/pointer then i handwrite. thats sad! :(
Great video. ! THANKS
You rock - as usual.
You are sooo amazing.how many people have you helped ???
You will never know
Please! explain in other video why? we subtract the mean from each value in the data set and square them to get variance of the data?
bro its 13 year old video 😆 you think he'd respond
@@techvishnuyt There's always a chance
The variance just tells you how far each point is away from the mean on average. Because distance cannot be negative, we square the differences to make them positive. I'm not sure why we are squaring the differences instead of just taking the absolute value tho
Edit: actually I think *standard deviation* is what tells you how far away each point is away from the mean on average (or at least it gives you a number very close to that). Variance just seems to be an intermediate step to get there
your videos are too good and i think u are doing a great job
I'll be gentle. Just tell me what you like.
I don't know why but I am in love this guy's voice.
And yeah the lectures being the first.
This is cool. You have helped me a lot. Thanks to you 😊
I've also watched your videos on several topics in physics. Galing nyo po!
I don't have enough words to thank you! You helped so many people, including me. Truly, thanks so much :)
This viedeo is literally part of my uni course lol
I been sick for the past week and my friends told me about this because they are learning at school so I got worried since they said there's a test tomorrow but this helped a lot THANK YOU now I'm ready
I don't understand the square root portion.
How is the square root of 200, 10?
watch the video properly the sq. root of 200 was not 10...it was 10√2.
Just wondering, is the Variance & Standard Deviation a human construct like Matrices to provide a standard way of comparison?
Squaring the difference between a data point and the mean to make it to a positive, then to square root the entire set seems arbitrary. I only say that because square root of (a+b)^2 does not equal square root of (a^2 + b^2). We start with (a-m)+(b-m)+(c-m) +... but we don't go back to that state. Squaring each difference then square rooting the entire set wouldn't bring us back tot he original data.
Hedel Torres I was also thinking bout this. Since I can't find anyway this makes sense in the sense of derivation, I also thought it was just a human construct
You're a rock star! I totally get it. Thank you.
how does the squire root of 400 become 2 ?
This is the "Population Standard Deviation"
For the "Sample Standard Deviation" we replace n with (n-1) to ensure that all desirable properties of an estimator are retained.
Wh7y do we need to square the differences in variance? If it's just to make it a positive value, we could have used absolute instead.
Khan academy at it again with an awesome explanation and breakdown of statistics. Thanks very much.
If only you guys could see how the teacher teaches this subject at my university...You'd hate this subject i guarantee. She straight up reads solutions from the guide book without explaining whats happening or why we are doing anything.... Thank You So Much Khan Academy!!!
You're so clear and cut through the jargon so well that it's actually making me mad. I spent so much time in college trying to understand this stuff and if I would have just watched these videos instead I can't even think about the amount of time and effort I would have saved. Great stuff
Oh my god, this never made so much sense before...thank you so much!
Sir can you please tell their applications in practical life
such a great breakdown!! thank you!! you explained every step so that I understand what I am using to get each answer.
Is it alright if the answer is Two decimal?
I love your explanation really but I am bit confused with SD (standard deviation) but I will go back toy book and listen to this again. Thanks 🙏🏿
It's summer I'm 13 and I'm learning it's my best summer yet
I understood standard deviation from my math book I just didn't see that variation was standard deviation without it being square rooted it's so easy
Thank you soo much! Your a life saver!!!
wrong formula it should be n-1
The most helpful explanation about standard deviation I've ever watched. Thank you so much, Sal!!!! You're the best math teacher in the universe.
now i get it thank you very much !
What is the software called which he is using?
Tommorw my exam 😅
Thank you so much. This is so helpful. I highly appreciate the time and energy taken to prepare this to make this available for free.
This is amazing! I thought I hated stat until I watched the video. It turns out I have a bad teacher lol . The teacher who made this video made it simple and conveyed the meaning in a great way! Thank you:)
I was out of class with my friends when my lecturer was teaching this thank you so much.
Thanks a lot! Really simple and useful comparitive explanation!
Any time you feel struck in mathematics, you tune into Khan Academy where Sir Sal explaining the concept so easily.Another day is saved,thanks to Khan Academy.
Thank you soo much man!!!! Came in clutch!
Currently a history major with a minor in political science. Took statistics in high school and again in college but this just made so much sense. To anyone reading the comments, watch frequency tables first and then start looking at this video. It takes15 minutes for both but you'll appreciate so much math quickly.
You saved my future and my mental health
Draw a graph of the stock price movement of the firm that you choose, show the summary statistics (including average stock price, standard deviation, the minimum value and the maximum value) in a table and briefly analyze them.
Can somebody help/? with this question? I have a data of a firm to analyze
Wasif Rana yeah sure )
Found this vedio in my 3rd year of med school and was saved in Biostatistics. Alhamdulillah
OMG! I love you! I finally understand this now!
So happy!
Dude, now im ready for my periodical test, tommorrow !! I really appreciate you pal !!!
very useful. I'm taking QUAN201 and I wish I had you as my instructor 'cause mine really sucks
Thank youuu omg I can take my exam tomorrow in stat without any doubts with my answers
I forgot. Why does -20 x 2 = 400, again? Ugh, I should know this.
two negatives equal a positive makes no sense to me.
Hi. It's been 2 months but...
Are u referring to the variance thing for the first set?? The (-10-10)^2?
It's bec (-10)+(-10) = -20
Then (-20) raised to 2 or squared makes it: (-20)x(-20)
Negative x negative = positive so:
(-20)x(-20) = 400
Idk if I answered ur question tho HAHAHAAHHAHA
hopefully you found that useful... it was the most easiest explanation I got on the internet..My university life started a few months back (online semester ft. Corona) and I am taking a Stat course right now. My teachers explanation was really vague, it's like he(my teacher) is trying to hide something from me. but this actually cleared everything up. Thanks Salman. One day, I will be great teacher like you inshaallah.
for the variance the formula should be divide by n-1 not just n ..now i m 😕
+cristianwero80 too late to reply....i already studied it...gave my exam....and passed it...thanks anyways!!!
Ha, watched Khan academy vids when I was 10 and here I am 6 years later using them to help me with my as levels
n-1 at denominator or just n please clear this for me
it is
variance should be 250 and 2.5 respectively and their respective standard deviations should be 15.8 and 1.58 respectively. You missed the (n-1) which should give you 4 instead of using 5 as the denominator. Great lecture though :)
Your explanation is very clear and simple to understand. Thank you.
You have been helping me pass university classes for the last decade.
You're a very important person in the world.
You spoke at a great pace and very clearly. This video was very helpful.
I would like to know what the answer to evilshenanegans' question is though.. and william's question on negative numbers and range...
Fantastic explanation I've always found range, variance, and standard deviation frustrating. This video really breaks down these concepts in a way that's easy to grasp. Please share more such videos. For anyone else struggling, this video is a game-changer. Plus, I've also been using free textbooks from SolutionInn to better understand these concepts, and they've been a huge help alongside this video. Pairing it with resources like SolutionInn, Chegg, or Course Hero offers extra practice and explanations that solidify your understanding. Thanks for making this topic less daunting!
The calculation for standard deviation and variance is not done right. For the variance u should (obs/mean)^2/n-1. The standard deviation in the example should be 15.8 and the variance 250 (first data set). Correct me if Im wrong...
I calculated -20 squared and it was -400. I am not saying you're wrong I just doubt that equation. But other than that you're an amazing teacher. Keep up the excellent work Khan!
The sample standard deviation of the dataset 2, a, 12, 18, and 30 is 10.8 (correct upto one decimal place), where a is an unknown quantity. Then, the value of the sample variance of the new dataset that is obtained by adding 5 to each number of the given dataset is __________.
you are an amazing individual, thanks for making it simple
Transcribed image text: If you have the following measures for two samples: Sample 1: mean = 15, variance = 7 Sample 2: mean = 7, variance = 15 Which sample has a larger range? ??? can anyone tell me the answer please