This channel provides useful and clearly explained info 100% for FREE. These people are literally investing their time and best efforts to create good content, yet people still find "what is wrong" and complain about it instead of appreciating the beauty of education available to everyone
LadyGagaSweetBaby not education, this to me is simply information to pass an exam, then never use it again. But of course im very grateful that mr khan did this for us
@@ubaidshah1910 because you won't go into a field that uses this concept millions of people still have to do this everyday as part of their job its used in real life
"[Standard deviation] gives us some measure of, on average, how far the numbers are away from the mean" The most important and useful part of the entire video for me.
Kahn - thank you! My favorite morning ritual for the last couple months has been eating steel-cut oatmeal, drinking coffee, and watching one of your videos. It wakes the brain up in a painless, entertaining way. I'm a piano performance major who once considered being a math major, but never went beyond Calc 3. Having your videos makes me feel like I'm just connected enough to that world I love!
Yo 13 years sense you wrote this how’s life now this comment is old and that’s crazy 1 year ago it came out when you’ll posted this comment it it’s been 14 years time flies also how is life now ya a adult now we’ll have a good day?
Realized this is a video in 2009 when I saw the Windows XP OS. Old but Gold. p.s. watching this series to reinforce my stat for machine learning/ data science ;))
I have to Say this Definitely, You just redefined my current way of Thinking about these Central tendencies and I am getting more and more Sense and am Reaching my Intention for Watching your videos in Particular.
Hello Sir, Thank you for this video series. I have looked at other basic statistical videos around this subject, but none of those have explained to this details. Normally a 10 minutes of video also looks long as a persons ages, but your presentation style and detail coverage has bound me to the video. I am still watching the 4th video but have started to get more interested in Stats. Your very purpose of making this video series has achieved more than expected.
The "n-1 division" is the "degrees of freedom". The reason for this is because you are dealing with a sample. A sample represents a population but it is not a 100% accurate representation that reflects the exact form of the population. So by taking the sample's size and take away 1, we are not underestimating the true value of the population, but rather be more accurate to present our sample standard deviation to be like the population's - making unbiased results. Hope this helped. Go Khan :)
"[Standard deviation] gives us some measure of, on average, how far the numbers are away from the mean" But in the world would you not just calculate exactly how far the numbers are away from the mean?
True but the thing is, sometimes it is not possible to do it for a whole population. Furthermore it is hard to say in one metric how much every point is how far away. That's why the standard deviation is a thing. It is an expression that says for this sample / population the spreadout is this.
woow i m currently taking the 6 sigma certifications exam class and to tell you the truth even my teacher couldn't explain this concept as clear as u did. U good!!! thumbs up
You are the best, i suddenly started my Master's in computer engineering and was i bout to withdrow, after finding what this guy is teaching in math and statistics i had a hop again, u are amazing man, truly amazing by all means, keep it simple like u r doing, u made math truly to be fun.
thank you, Khan! with you, i understand these concepts so much better than a lot of times in my mother tongue. pls keep going. you've promised geometric and harmonic mean in the 1st video) and that's exactly what i need to brush up.
I'm a systems engineer in a 3000 level statistics class with a professor who can barely speak English. I have never taken a statistics class before so I find it rather difficult but I learn more from these videos than my prof. This guy can teach it so much better because he knows how to break it down on a beginners level. Thank you Khan!
I don't mind this type of video actually. I can still learn stuff without high resolution. Gosh people these days. Thanks for your hard work Sal. Best professor ever!
I am taking my 1st and last class in statistics. This instructor breaks it down and explains clearly I wish my professor had the same teaching techniques
you are the best 1000 times better than all these professors I've had and paid so much money to, you made me GET IT all the way....I love you for that :))))))
Everytime I watch one of his lectures I feel not worthy. I wish I was as intelligent as him; I do great in school but this guy knows EVERY subject as if it is as easy as breathing! I envy him with every bone in my body!
So what's the difference with variance and standard deviation? I know variance is how far away below or above it is from the mean, but what about standard deviation? Thanks! Love the work so far, learning more than I could have imagined
@jazz77ol I just answered myself. Standard deviation is pretty much the same thing as variance Except it is the square root value of The variance. Further to calculate the variance one would uses the whole population value where the standard deviation 'requires' just the sample value. I thought someone else may have the same confusion and this might help.
Not only that. You can rerun our friend here as often as needed. While i do have my physics degree now for over twenty years I am incredibly thankfull for this channel. Mr. Khan is everything I ever dreamt of when i was studying. Not to mention school. Merself I cannot decide if to jump out of the chair or not to leave it at all. Positively addictive stuff. have a nice day silk ;-))
thank you for saving my time :) i really understand your tutorial {from Egypt}. i study computer science and it really helps me when i don'd understand from my instructor
you know what your the best. I really love all your videos. Honest and they really help me a lot hope youl never stop what you are doing. Your really helping a lot of people
@ion010101 That's okay, you would say those guys way out there are "x standard deviations from the mean". One of the reasons we use standard deviation in the first place is to determine whether or not a value is "unusual" or not, so a couple guys in a different galaxy don't invalidate the standard deviation at all. Think of sd as a measuring stick calibrated for a specific job. It's only as long or as short as it needs to be.
i NEVER thought i'd understand variance & SD...thank you soooooooooo much. I thought i was done with math 14 yrs ago but it's reared its ugly head. Thank you for making it less painful ;)
I am beginning to wonder why pay $6000 per semester when you can youtube anything and get a much better lesson than our overpaid professors!! i am going to start donating to Khan
Hahahaha please! My teacher uses this guy to teach us, never the less you are awesome ;) With you´re help I finished a 9 page statistics essay in time. Thanks man!
Population is always divided using N and n-1 is used to divide sample. You just have to know whether the data is sample or population. If it is sample, then use n-1 and if it is population, then use N. Sorry for late reply :)
very good explanation. I feels that i shouldn't go to my statistics lectures. because i can understand those stuffs better, than in lectures. thanks. keep up your good work. Cheers.
This info is not just for passing an exam . It clearly is reaffirming what one either already knows, filling in the gap of mis understanding to better understanding or an introduction to something new for better familiarity. I get it. Besides if yr just doing it to pass an exam without realizing you learned something about yourself well you have missed the point for yourself and what khan academy is trying to accomplish , especially those who are visual learners more so than audio learner Stepping down off the soapbox now📦
In other words: We are doing root of variance just to get it into the right units presumably that the initial units (not squared) represent the right statistical measurement, thus making variance wrong? It's all for the intuition of what seems right and wrong?
I have a question. See if the numbers 1,2,3,4 and 2,2,3,3 were each on separate tetrahedral dice and you rolled them together, which one would have the greatest probability of winning and how would you work that one? Would standard deviation be taken into account?
I watch different math videos, and after a while I noticesDthey are all made by the same person, Sal Kahn. How does he find time to do anything else when he is making thousands of these very clear teaching videos?
