ANOVA 1: Calculating SST (total sum of squares) | Probability and Statistics | Khan Academy

[@chriskeaten1126]

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[@domingo2977]

I think Quantum Physics

[@ElizaberthUndEugen]

Atcually they don't do computer science, unfortunately.

[@walterperrell4898]

How's that successful thing coming along? We need an update!

[@phaego_san]

I will too!

[@volmo852]

Are you successful yet?

[@AdrienneJustineXO]

Wow you are an amazing human being. You've been my go to since 2009 . Thank you for making such amazing tutorials available to us students at no cost. :)

[@snehat6050]

You've been teaching me since my grade 11 in 2013 and now my MBA in 2021. Thank you so much sir

[@Shinyflubba]

I havent seen your videos in so long but I was curious about some statistical techniques and KZbin's search results didnt have you even top 10, but I remembered you being caring and knowledgeable in your videos and I am glad I looked you up specifically. Time to look through the rest of your ANOVA videos. Thank you so much!

[@chlorind]

I always watch your video when I didn't get in school or college since high school. Now I'm in college and still have your explanation so helpful for my academic! THANK YOU VERY MUCH!!

[@kyladuplessis1810]

This video literally saved my life a day before having to write a big test. Thank you so much!

[@alkalait]

Finally I have an intuitive sense of why computing the sample variance of a dataset involves dividing the sum of squared distances from the sample mean by N-1. Thank you.

[@giuseppejoseph8890]

I'm going to start using your guides. I got a 78 on my first exam (everything averages to atleast an A- with my labs etc) but I want to do better on the following exams. Besides, I have Experimental next semester and it's a more intense course for psych majors. Thank you for this!

[@ayshajohn2439]

Now I understand what m*n-1 is for thanks it will be much easier to remember now.

[@BigGulp]

Disclaimer - the "mean of means" (average of multiple means) is only = to the grand mean (average of all data points) when each group has the same number of data points (in this case they all have three).

[@felixfelix8905]

every nice video. Today is my FIRST day to understand SST!!!!!!!!! THANK YOU ,SIR!

[@shbp21]

This Man right here is the REVOLUTION of education!

[@sistranquility]

You make everything so simple! I wish you could teach in Swedish terms but this is already Sooo helpful God bless you

[@aladdinkayqubad1645]

Get an internship and translate everything in Swedish...

[@w4yn6]

I recall that for chi square, the degrees of freedom was (m-1)(n-1). I don't understand why this should be different.

[@kunalmittal1321]

Here is only 3 columns

[@jimmyhaotran123]

D.f for this specific case (SST) which he didnt use any other types of mean, but the mean of all the data points combined divided by the number of data points which is 9. Therefore d.f is just n-1. The reason behind this is just that if you know the mean, it simply means after knowing 8 data points, the 9th one has to be an exact number which you could calculate to match with your mean, hence only 8 numbers are free to become any numbers, while the last number isnt free. This is also why you later will find (m-1)(n-1), I dont know if the formula is correct, but by my intuition this is also showing you something similar, when you know the mean of each of the sets individually, that takes away some of the freedom to variate the numbers.

[@JenryLuis]

@@jimmyhaotran123 Thank you very much, jaja I was searching for this explanation! now all have sense

[@Tubeytime]

This man is a treasure

[@vman049]

Great video (as always with Khan Academy) BUT the mean of means in general is not equal to the grand mean. For them to be equal, you need to have the same number of data points in each group. Otherwise, you must calculate the grand mean by simply averaging together all the values in all the groups.

[@soumilyade1057]

Till date, the best coverage of ANOVA

[@kennchen2925]

This is so much better than my professor's lectures.

[@KiddSteely]

Sal has been there for me when my professors fail at doing their job. If nobody got me, I know Sal got me

[@Salvia02390]

You are saving my life in Econometrics! Thank you!

[@nanuhk00]

SAL KHAN IS AN ACTUAL LEGEND

[@logpos]

THANK YOU! I wish my professor could explain it as well as you could!

[@tical2399]

Please add a few more social science videos such as Geographic information systems or urban planning.

[@delcapslock100]

What would be great for both the regression and anova series would be for Sal to show how they both apply CLT, since they both are dependent on CLT but how is not intuitive.

[@xverc3x]

Thank you so much for all those videos. You helped me a lot !

[@HerdingDogRescuer]

Totally lost me at the end there with the degrees of freedom and variance bit. It was scattered and confusing.

[@sixtysixx3933]

degrees of freedom generally just means how many observation is free to be whatever it wants to be given known the mean, in this case there are just 8 observation that could go freely, the last, or ninth number must be a specific number after knowing all other 8 numbers, because of the mean. The case with variance is because if you play around the SST formula algebraically you will find that the formula is exactly the same as the variance.

[@abhishekpnambu]

@@sixtysixx3933 but in the last video he said degrees of freedom=m-1*n-1

[@atharvawaghaye2877]

very informative

[@carlosvalencia431]

Thank god you uploaded this, If I pass my test tomorrow morning; I´ll invite you a drink. Thanks bro ;)

[@alabatchi1]

So what happened? Did you pass? 🤣🤣

[@10xbelegt]

I dont know what I'm doing wrong but with data sets of a = 21, 15, 16, 20 -> mean = 18 b = 6, 10 -> mean = 8 c = 17, 13, 8, 10 -> mean =12 Grand mean would then be All data point/10 = 13.6 But the mean of the means is (18+8+12)/3 = 12.6

[@10xbelegt]

Edit: To calculate the global mean out of the mean of means, the means of the samples must be weighed. in My example: (18*4 +8*2 + 12*4)/(4+2+4) -> 13,6

[@andreia7422]

I have N=20, k=4 (m1=4, m2=8, m3=12,m4=7) and SSB=22. How do i find the value of SSW?

[@discopowerpack]

In my exams at uni we often have to fill in the blanks of the anova summary table. is it possible to calculate SStreat when you only know DFtreat, DFerror, and MSerror?

[@statdata3973]

This is great, very clear and informative!!!

[@jianneestradaurubio446]

thank u so muchh huhu ilove uuuuu

[@BarrettOwenW]

dam you're good Khan, was waiting for this.

[@mdixon007004]

awesome...thank you so much

[@merarig9572]

Thank you so much for this!

[@allantorrescamba7958]

Shouldn't you be using the greek letter of "m" for the mean and not the letter "x"? The letter "x" could represent the independent variable and that could be confusing.

please make a video about how to calculate wards method

[@shariealcala9558]

you explained it very well ^_^ .. thank you!

[@209yangyang]

thanks!

[@zainnoman1698]

sir is it possible to answer this qs with Combined mean ??

[@MsPerva]

Omggg i love the way you teach 🌹🌹🌹

[@jaafaridris6205]

Thanks

[@bakhodiryakubov3981]

So degree of freedom for ANOVA is (MN-1) whereas d.f. for Chi-squared is (M-1)x(N-1)?

[@nnynie]

can anyone help me with this question Make up a sample of size n = 7 for which the average is −13 (note the (−) sign). Not all 7 numbers should be identical.

[@henryibeky-edu7503]

13 years later and I am here 🔥

[@divyagowda836]

You are really genius Sal. Thank you for all your hard work and efforts in putting across such amazing videos.

[@nayanikasarma]

You're awesome

[@ZubairAhmad-mi8wi]

productive talk

[@thecoldzero911]

You should start your own university. I’ll attend classes that i’m sure will make sense 99% of the time.

[@mr.laqueash169]

absolute banger

[@Thenikhilkhurana]

Omg!! Dude ur awesome :D

[@charlien2573]

Confused do I divide the SST (30 in this example) by the DF? and that gives me the SST?

[@YousifKorkis]

Charlie Marie no that will give you the sample variance

[@charlien2573]

HAHA hi Yousif, I very slowly realized this but thank you

[@chinyuan8529]

I think the title should be Calculating TSS ( Total Sum of Squares )

[@basity123]

The more i watch his videos the more i hate my prof at school .. lol

[@tualibudinenordinebacai3414]

whats is the mane of progam the teacher use.

[@neilnemesiobaliuag7490]

SST was not equal to X double bar, you were not able to prove it then you ended to computing df

[@Dan7s]

somehow it doesnt work.

[@gamingguy8595]

I dont understand m.n-1 degree of freedom

[@jianneestradaurubio446]

u saved my life away from singko HAAHHAAH

[@CodeCommand]

without doubt the worst way to calculate SST.

[@خالدعليعبدعليالحلو]

How 1+4+9=14???

[@rivariad]

thanks!!