For PL3, I have placed the z-score video *FIRST* because knowing what a z-score is conceptually does not require knowing how to calculate nor need the formula for standard deviation. The entire point is that it is just an _arbitrary unit of measure_ like a ruler. You can make your own playlists from individual videos if you prefer something in a different order. Thanks!
These are the most value educational contents on RUclips. I took statistics in university, but your explanations and examples are second to none. I don't know if you still make education content and if you do, please keep them coming. Thank you so much and God bless.
I appreciate you so much. Not only the way you start of your videos but bringing down the walls and defenses when struggling but also the information you present, and extra mile you go. Thank you!
I spent whole year in Statistic class but couldn't understand why and how we use Standard deviation but in few mins, you explain in wonderful way. I can't forget in rest of my life.
@@BrandonFoltz The playlists are still out of order. PL3 starts with Z-scores, then has three videos on standard deviation, but the z-score video assumes you've already watched the standard deviation video and understand what they are and how to calculate them. Had to give up on it half way through.
@@BrandonFoltz i see the z-score one is still positioned at #1, can you please rearrange for others? also, your vids are absolutely helpful for layman like me, thanks for your hardwork.
Hola, Brandon. Aunque no domino totalmente el inglés, tus videos son muy sencillos de entender y no sabes lo mucho que me han ayudado en mis estudios. Solo quisiera agradecerte el gran esfuerzo que has hecho con todas tus playlists de estadística.
Sir, I should leave a thank you at all your videos, but I don't want to spam you. YOU ARE AWESOME! I got a textbook teacher that believes its the books duty to get info across. Our class is something like "Go home read pages x-x if you have any questions mail me, test on Tuesday." .... needless to say I found you! and your videos are AMAZING!!!! :) THANKS SOOOOO MUCH!!! :D
Hi Brandon. First of all thank you for making these videos on statistics. It is nicely done. What I would like to point out is that there are still some points unclear. I mean you should make a video on variance maximul likelihood estimation to make clear why the (m - x) is divided by (n-1) instead of "n". Since you are trying to make things clear I consider this to be significant imperfection. If you have already done so excuse me. Thanks, Mario from Czech Republic
Hi Brandon, I highly appreciate your videos but there is a small error in this one. The greek letter sigma should be used only for the standard deviation of the population and not for the sample. In this case the small letter "s" should be employed.
Hi Brandon. Amazing videos! You have all what is needed - what, why, how and when. You make the options connected - simply put the complicated formula connected with the simple way of calculation using table. Great job! You explain very clearly and thoroughly. I love it. I have shared with many of my friends. Again thank you so much for making these available.
Hello! Oh thanks so much. :) Everyone has their own teaching and learning style so I am glad you found that what I do matched your learning style. Hang in there and keep on learning; never stop. :D All the best! - B
I wish I had saw your vids before I dropped stats! Guess I'll try again with you as my real teacher and the community college hack that just grades the tests.
Hi Mario! Thank you for your comment. My goal has always been to introduce introductory statistics topics in a way that helps students grasp basic fundamental concepts without turning them off to stats. I also try to stick with the topics in an Intro Stats class (at least here in the States) would cover. The MLE, while a valuable topic, is beyond the horizon of what I set out to do in my videos for my intended audience...at least at this time. :) I may come back to it. All the very best! - B
Didn't you transpose the numbers when calculating % of Class "B"? Final answer in the light pink area should be 5.58%, not 5.85%. I'm finding your videos very helpful, since I am currently flunking STAT200 on line. Thanks for all your work!
If the classes represented population we should have used μ and calculate our standard deviation σ with n population size. If the classes represented sample then we should have used x_bar and calculate s with n-1 sample size. You said yourself you use sample variation so s^2 it is then.
HI Brandon. Liked your video on Chi-square, after struggling to understand from various sources your video was the most comprehensive and clear explanation . Thanks. I am into basic data analysis and want to relate using statistic Since i want to start using statistics is it possible give an order in which one should go about carrying out statistical analysis as in which test to use under what circumstances etc. Meanwhile let me watch some more of your video's
Brandon - these videos are excellent and exactly the refresher course I need. Where should I start in playlist 3. If I was to hit the "play all" button in You tube, I would start with Z-scores (which refers to a previous video about standard deviations followed by SD and NFL field goals 3/3, followed by SD and NFL field goals 2/3, etc. Are they in the wrong order ? But thanks again....
Hello Brandon First of all, your videos are really great. I have started to watch the full series and now on video 7 of the whole playlist. Just to highlight one issue here please. When I click on block post and excel file as given in the details above, it gives "page not found". Can you please fix this. Thank You Gaurav
I have a question why in case of population on calculating the standard deviation we divide by n(number of data sets) but in case of sample we only divide by (n-1)
Hi Brandon thank you for creating these videos! They have been very useful revision material:) Tried to download the link for the excel file but it's broken could you upload it again?
what's the difference between this regular variance and discrete random variable variance if they are both discrete like this case here and which one to use? thanks
Hi Brandon, here you've used n -1 while calculating SD & Variance. But in the simple liner regression videos, you've used n. (5th video in SLR to be specific)
Basically for calculating Sample Standard Deviation we use n-1 and for Population Standard Deviation we use n. So the logic behind that is since the sum of deviations (Not Standard Deviations) i.e. x-xBar is 0. Therefore if we know the Sum of first n-1 deviations last deviation can be easily found. So when to use what ? => If we know the true mean i.e. the mean of the population we use n AND if we don't know what the true mean we calculate sample mean and use n-1 for computing Standard Deviation.
Hi Sir. Appreciate the effort and your dedication. Which tool do you use for making the arrows and recording your sessions? It looks like a manual pen?
Hello Brandon!! Highly informative video. I just have a quick question. When u calculate the standard deviation to be, say, 7.9. what do u infer from it?? Does it mean that the data points are spread across +/- 7.9 from the mean (which is not the case here) or is the SD just a number that gives you an idea of the extent of the spread ? Many thanks !!
I"m not sure if you read this or not but i"ve a question regarding the formula of SD and Variance which doesn't have n-1 then only have n. so what is the difference between them and this and which is more accurate
Hi! The difference is between sample variance ( _n-1_ ) and population variance ( _n_ ). Without getting into the weeds, we correct for the fact we are only using sample data from a population by taking away a degree of freedom. However, as you may notice, as n becomes large the difference is negligible. Say if _n_ = 10, then _n-1_ = 9 (10 vs 9). But if _n_ =100, then _n-1_ = 99 (100 vs 99). But technically, if using sample data for the VAR or SD then _n-1_ should be used.
@@BrandonFoltz Thank You so much! and i really love your videos currenlty i"m doing masters in Data Science in Germany and your videos are great help for the exams.
Hi Brandon, I have a question about standard deviation in a skewed distribution. Your example of test scores defines them as being out of a total possible score of 100, with a mean score of 85 and a SD of 7.9. That would mean that two SDs above the mean would be 100.8/100 which is not possible. How does one rationalise that with real-world data? I actually have a problem similar to this with my own data and I would be grateful for your help! Many thanks.
Hi Brandon, the link to the excel file , leads me to a blank page and it says" nothing here" could you pls share the path where I can find the excel file ?
I want to know how to sum or subtract means and calculate the new standard deviation and variance taking into account the previous ones. can that be done? do you have a video?
Great, great videos, Brandon. Thanks. I think you should make clear the order for the videos to be seen. IMHO, videos now numbered 1, 2, 3, 4 should be watched 4, 1, 2,3 In video #2 "Statistics 101 Standard Deviation and NFL Field Goals - Part 13.mp4" 11'45'' you make 0 squared to 0 = 0; but 0 squared to 0 = 1, isn't it?
Sorry, I meant 2,,3,4,1. That's the order to watch the videos so that every concept comes after the previous one has been clearly explained. Anyway, a great course indeed
Hello! For sample data, N is a biased estimator. Therefore n-1 is used for the unbiased estimator. There are theoretical and mathematical reasons for that, but what it comes down to are biased vs unbiased estimators for small sample sizes. Of course as n increases, n-1 basically becomes N, which is why after a point, a larger sample converges to N.
Agreed. For example Statistics PL03. We already can see that Standard deviation in the list starts from 3/3 to 1/3. That raises a question - is the list backwards? On whole other matter, these are great! Do please continue. I would love to see you explain ARIMA model, because i can't put my head around that one.
Tomas Romas Sergey Markov Thank you both for your comments. I did check and you both correct about the order being messed up. Not sure how that happened since I add them as I do them. It is fixed now though. Thanks! ruclips.net/p/PLIeGtxpvyG-JMH5fGDWhtniyET88Mexcw
Oh, and thank you so much. These videos are outstanding! I am taking a graduate-level statistics class, and this material is so much better than the material my university is providing.
For PL3, I have placed the z-score video *FIRST* because knowing what a z-score is conceptually does not require knowing how to calculate nor need the formula for standard deviation. The entire point is that it is just an _arbitrary unit of measure_ like a ruler. You can make your own playlists from individual videos if you prefer something in a different order. Thanks!
Hi. I suggest to make this as first lecture instead of zscore. Thank
These are the most value educational contents on RUclips. I took statistics in university, but your explanations and examples are second to none. I don't know if you still make education content and if you do, please keep them coming. Thank you so much and God bless.
I appreciate you so much. Not only the way you start of your videos but bringing down the walls and defenses when struggling but also the information you present, and extra mile you go. Thank you!
I cannot tell you how much your videos are helpful. You should be paid.
I spent whole year in Statistic class but couldn't understand why and how we use Standard deviation but in few mins, you explain in wonderful way. I can't forget in rest of my life.
Great videos. Very informative. I recommend these videos to anyone trying to get started with data and data science
teaching from the core of his heart, beautiful and simple illustrations, Thank you very much SIR
please arrange your videos in playlist so that viewers may get proper sequence of all videos sorted according to subjects.
Hi Ahmad! Actually they are organized into playlists. You can find them here: ruclips.net/user/bcfoltzplaylists
@@BrandonFoltz The playlists are still out of order. PL3 starts with Z-scores, then has three videos on standard deviation, but the z-score video assumes you've already watched the standard deviation video and understand what they are and how to calculate them. Had to give up on it half way through.
@@BrandonFoltz i see the z-score one is still positioned at #1, can you please rearrange for others?
also, your vids are absolutely helpful for layman like me, thanks for your hardwork.
@@BrandonFoltz After 6 years still the same.
Your video/explanations made it really to understand the above topic. Thank you!
I really thought I would fail my Stats class...until I found you & your videos. Thank you so much!
Hola, Brandon.
Aunque no domino totalmente el inglés, tus videos son muy sencillos de entender y no sabes lo mucho que me han ayudado en mis estudios. Solo quisiera agradecerte el gran esfuerzo que has hecho con todas tus playlists de estadística.
Good video. Easy to understand w/ clear demonstrations.
Sir, I should leave a thank you at all your videos, but I don't want to spam you.
YOU ARE AWESOME! I got a textbook teacher that believes its the books duty to get info across. Our class is something like "Go home read pages x-x if you have any questions mail me, test on Tuesday." .... needless to say I found you! and your videos are AMAZING!!!! :) THANKS SOOOOO MUCH!!! :D
Hi Brandon. First of all thank you for making these videos on statistics. It is nicely done. What I would like to point out is that there are still some points unclear. I mean you should make a video on variance maximul likelihood estimation to make clear why the (m - x) is divided by (n-1) instead of "n". Since you are trying to make things clear I consider this to be significant imperfection. If you have already done so excuse me. Thanks, Mario from Czech Republic
I like they way he made the math more visual. It made it much easier to understand.
Hi Brandon, I highly appreciate your videos but there is a small error in this one. The greek letter sigma should be used only for the standard deviation of the population and not for the sample. In this case the small letter "s" should be employed.
Exactly what I was thinking! Thank you for saying this. :)
Hi Brandon. Amazing videos! You have all what is needed - what, why, how and when. You make the options connected - simply put the complicated formula connected with the simple way of calculation using table. Great job! You explain very clearly and thoroughly. I love it. I have shared with many of my friends. Again thank you so much for making these available.
Hello! Oh thanks so much. :) Everyone has their own teaching and learning style so I am glad you found that what I do matched your learning style. Hang in there and keep on learning; never stop. :D All the best! - B
clear explanation of standard deviation. easy to understand
I wish I had saw your vids before I dropped stats! Guess I'll try again with you as my real teacher and the community college hack that just grades the tests.
Very interesting video. Looks like I have more to learn...
Hi Mario! Thank you for your comment. My goal has always been to introduce introductory statistics topics in a way that helps students grasp basic fundamental concepts without turning them off to stats. I also try to stick with the topics in an Intro Stats class (at least here in the States) would cover. The MLE, while a valuable topic, is beyond the horizon of what I set out to do in my videos for my intended audience...at least at this time. :) I may come back to it. All the very best! - B
Very helpful video and explanation for Standard Deviation. Makes sense!
Neat! Never thought I would understand Variance and Standard Deviation!
i believe, this playlist need to reordered. others your channel is great. Thanks
Very thorough explanations!
Your videos are great. Extremely well articulated and concise, thank you
Mean not average. Good class examples used to describe variance and standard deviation.
donated! because you teach better than my prof!
Agree with Mario, the video would be more helpful if you could explain why it is "n-1" but not "n".
can anyone tell why we have used population standard deviation in sample standard deviation formula?
Didn't you transpose the numbers when calculating % of Class "B"? Final answer in the light pink area should be 5.58%, not 5.85%. I'm finding your videos very helpful, since I am currently flunking STAT200 on line. Thanks for all your work!
If the classes represented population we should have used μ and calculate our standard deviation σ with n population size.
If the classes represented sample then we should have used x_bar and calculate s with n-1 sample size. You said yourself you use sample variation so s^2 it is then.
The coefficient of Variation, is that similar to a z score?
HI Brandon.
Liked your video on Chi-square, after struggling to understand from various sources your video was the most comprehensive and clear explanation . Thanks. I am into basic data analysis and want to relate using statistic
Since i want to start using statistics is it possible give an order in which one should go about carrying out statistical analysis as in which test to use under what circumstances etc.
Meanwhile let me watch some more of your video's
Great video .. this is such helpful lectures. Thank you very much for doing that
thank you so much like this simple explantion
Hi Brandon, great videos thank you 😊 , can't find the file on your page. tried to download it through the provided link.
Very informative
Brandon - these videos are excellent and exactly the refresher course I need. Where should I start in playlist 3. If I was to hit the "play all" button in You tube, I would start with Z-scores (which refers to a previous video about standard deviations followed by SD and NFL field goals 3/3, followed by SD and NFL field goals 2/3, etc. Are they in the wrong order ?
But thanks again....
Hello Brandon , love your video but it would make it easier of you would put the playlist # and video # under the Title- Many thanks
Hello Brandon
First of all, your videos are really great. I have started to watch the full series and now on video 7 of the whole playlist. Just to highlight one issue here please. When I click on block post and excel file as given in the details above, it gives "page not found". Can you please fix this.
Thank You
Gaurav
I have a question
why in case of population on calculating the standard deviation we divide by n(number of data sets) but in case of sample we only divide by (n-1)
Hi Brandon thank you for creating these videos! They have been very useful revision material:) Tried to download the link for the excel file but it's broken could you upload it again?
what's the difference between this regular variance and discrete random variable variance if they are both discrete like this case here and which one to use? thanks
Hi Brandon, here you've used n -1 while calculating SD & Variance. But in the simple liner regression videos, you've used n. (5th video in SLR to be specific)
Basically for calculating Sample Standard Deviation we use n-1 and for Population Standard Deviation we use n. So the logic behind that is since the sum of deviations (Not Standard Deviations) i.e. x-xBar is 0. Therefore if we know the Sum of first n-1 deviations last deviation can be easily found. So when to use what ? => If we know the true mean i.e. the mean of the population we use n AND if we don't know what the true mean we calculate sample mean and use n-1 for computing Standard Deviation.
Hi Sir. Appreciate the effort and your dedication. Which tool do you use for making the arrows and recording your sessions? It looks like a manual pen?
Thnks love from india
Thanks for the help!!
Great Videos!
Hello Brandon!! Highly informative video. I just have a quick question. When u calculate the standard deviation to be, say, 7.9. what do u infer from it?? Does it mean that the data points are spread across +/- 7.9 from the mean (which is not the case here) or is the SD just a number that gives you an idea of the extent of the spread ? Many thanks !!
I"m not sure if you read this or not but i"ve a question regarding the formula of SD and Variance which doesn't have n-1 then only have n. so what is the difference between them and this and which is more accurate
Hi! The difference is between sample variance ( _n-1_ ) and population variance ( _n_ ). Without getting into the weeds, we correct for the fact we are only using sample data from a population by taking away a degree of freedom. However, as you may notice, as n becomes large the difference is negligible. Say if _n_ = 10, then _n-1_ = 9 (10 vs 9). But if _n_ =100, then _n-1_ = 99 (100 vs 99). But technically, if using sample data for the VAR or SD then _n-1_ should be used.
@@BrandonFoltz Thank You so much! and i really love your videos currenlty i"m doing masters in Data Science in Germany and
your videos are great help for the exams.
Hi Brandon, I have a question about standard deviation in a skewed distribution. Your example of test scores defines them as being out of a total possible score of 100, with a mean score of 85 and a SD of 7.9. That would mean that two SDs above the mean would be 100.8/100 which is not possible. How does one rationalise that with real-world data? I actually have a problem similar to this with my own data and I would be grateful for your help!
Many thanks.
Hi Brandon, the link to the excel file , leads me to a blank page and it says" nothing here" could you pls share the path where I can find the excel file ?
Yes me too, I need to practice on excel
Why divide by n-1, in calculating standard deviation should it not be n
What is the difference between (standard variation and the population variation) I'm confused with the ( S and Sigma ) symbols and thank you so much.
Pls refer to the video in playlist 1. Sigma is the standard deviation in population, while S is the standard deviation in samples.
I want to know how to sum or subtract means and calculate the new standard deviation and variance taking into account the previous ones. can that be done? do you have a video?
I'm having a hard time finding the excel for the NFL example, can you advise where it is?
4.19 sec. in the clip.... both example are same. its by mistake but plz correct it.
Great, great videos, Brandon. Thanks.
I think you should make clear the order for the videos to be seen. IMHO, videos now numbered 1, 2, 3, 4 should be watched 4, 1, 2,3
In video #2 "Statistics 101 Standard Deviation and NFL Field Goals - Part 13.mp4" 11'45'' you make 0 squared to 0 = 0; but 0 squared to 0 = 1, isn't it?
Sorry, I meant 2,,3,4,1. That's the order to watch the videos so that every concept comes after the previous one has been clearly explained. Anyway, a great course indeed
Dear Professor, I didn’t understand why there is n-1 in the formula of SD i saw in books it was written N . I want to know what is the difference.?
Hello! For sample data, N is a biased estimator. Therefore n-1 is used for the unbiased estimator. There are theoretical and mathematical reasons for that, but what it comes down to are biased vs unbiased estimators for small sample sizes. Of course as n increases, n-1 basically becomes N, which is why after a point, a larger sample converges to N.
Professor @@BrandonFoltz , Thank you so much for your wonderful esxplanation. It really made me clear.
Hi.. where can I find Excel used in this tutorial?
Manisha
Love from India could you Please check File is not Available getting Error 404
please come up with new videos
Hi Brandon, the link to Excel is dead
The link is not working.
all videos are mixed up! no begining, no end
Agreed. For example Statistics PL03. We already can see that Standard deviation in the list starts from 3/3 to 1/3. That raises a question - is the list backwards?
On whole other matter, these are great! Do please continue.
I would love to see you explain ARIMA model, because i can't put my head around that one.
Tomas Romas Sergey Markov Thank you both for your comments. I did check and you both correct about the order being messed up. Not sure how that happened since I add them as I do them. It is fixed now though. Thanks!
ruclips.net/p/PLIeGtxpvyG-JMH5fGDWhtniyET88Mexcw
@@BrandonFoltz Is z-score the first or last video in this sequence? It's showing as the first.
What's to say. SD rules.
The link to the excel file seems to be dead. I get a 404 error page when I click on the link.
Oh, and thank you so much. These videos are outstanding! I am taking a graduate-level statistics class, and this material is so much better than the material my university is providing.