How to Calculate Standard Deviation and Variance by Hand

In this video, we'll learn the steps to calculate the four main measures of variability by hand: sample variance, sample standard deviation, population variance, and population standard deviation. Doing so will also require us to find the sums of squares (SS), which we'll also discuss.
PDF Guide illustrating how to calculate sample standard deviation: drive.google.com/open?id=1mMG...
PDF Guide illustrating how to calculate the other measures of variability: drive.google.com/open?id=125L...
Link to full Google Drive folder of all PDF Guides I've written for stats: drive.google.com/open?id=1Dns...

[@donnaspenader6528]

I have been trying to learn this for weeks and until I stumbled across your video, I could not understand it so I can’t thank you enough I’ll look forward to more of your videos. Thank you again again.

[@marianacosio2068]

Although statics still gives me a headache, I have to say I have no clue what I would have done if I didn't find your channel! Thank you SO much for explaining everything as simple as you can!!!!

[@GSMonkey]

Never learned about standard deviation before, but need it for a report i am making, and after your 2 videos, i feel i already have a pretty good understanding of it and know how to use it practically. So big thanks from me :)

[@Azminsonu]

You are the best thanks for your brief explanations life saver!! Literrally better than my professor ❤

[@priakaushal2071]

i've never has stats so easy. finally i understood why we did what we did. my teachers made it sound so darb and boring without the logic. een though you didnt get into it a lot, you made it clear as water. thank you so much. youre a great teacher. in india we call a teacher Guru, ergo, dhanyawadam guru ji. (thank you, dear teacher).

[@samuraicop4930]

Lol

[@Sandylaraaaa]

Thank you Daniel!! You explain it so well and make it easy to understand 🙌🏽

[@francesem1minuto235]

I had some statistics class in my life, but I never understood these basics so good. Thank you!

[@hipolitonovido8651]

I love your videos. How i wish i found it when I'm still studying

[@nathanheide8937]

Very useful videos! Thank you!

[@anikenejoseph4785]

this is beautiful. well explained and simple to follow

[@ayasosseyalaoui759]

Thank you very much for these good explanations🙏. It was very helpful

[@ahmedfathy4265]

you are fabulous in illustrating information

[@TheIresh]

Very good lesson. Please do more lessons like this. Thank you!

[@iqraqadeer5296]

finally i understand the terms. thank u so much

[@kmoody5012]

You’re awesome. Thank you!

[@jacekyle3131]

Only One Word: AMAZING!

[@blairt8101]

the best teacher

[@nayelinunez1294]

THANK YOU FOR THIS 😭😭

[@jennybarrett2148]

Thank you!

[@shishi1976]

Thank you very much !!!! :)

[@Ankit_Singh_09]

Thank you sir : )

[@robert6090]

Thanks!

[@AnomalyAtYourTemple]

TY. ❤

[@cindy_the_diver]

Thank you sir

[@ramkumarshah8825]

Thank you

[@curiousmonkey8485]

Why are we subtracting 1 from N? Why guesstimate it in that direction instead of +1 for example?
Thank you very much for teaching us!

[@DanielStorage]

Great question! Look up “Bessel’s Correction.” 😊

[@mursalmrasid]

TQ

[@ilsabyrd5646]

If you have multiple rows of data (two rows of Cups data instead of one) would the population variance use the sum of squares for all data together?

[@journeyto...5627]

Hi, a really great video about statistics ...I can't understand how just by putting (n-1) will approximate the sample to population SD or Variance ...plz tell

[@DanielStorage]

Great question! This is called Bessel's correction, and is basically used to adjust for the fact that, when using the sample mean in the formula for variance, we almost always underestimate variance (except when the sample mean equals the population mean). This is because the data in your sample will inherently gravitate closer to the sample mean to the population mean. Dividing by n-1 instead of n reduces that bias.

[@journeyto...5627]

ok but can you share a case where underestimation happens in sample ?

[@DarkPrincess_M]

​@@DanielStorage doesn't n-1 overestimate the variance?

[@kmoody5012]

When you got 22.4, why didn’t you subtract from x bar (2.6)? Was that not needed?

[@DanielStorage]

Kristen Moody Correct! This is not needed because 22.4 is the *entire* numerator of the formula. Creating the table leads you to “the sum of the squared deviations from the mean,” which is all you need for the numerator. I hope this helps!

[@kmoody5012]

It definitely did and does! Thanks a lot!👍🏻

[@juliab.6923]

I think you just saved me from dropping out of college

[@DanielStorage]

It's moments like these that make it all worth it.