Calculating correlation coefficient r | AP Statistics | Khan Academy

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Calculating correlation coefficient r. Intuition behind the calculation and r.
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AP Statistics on Khan Academy: Meet one of our writers for AP¨_ Statistics, Jeff. A former high school teacher for 10 years in Kalamazoo, Michigan, Jeff taught Algebra 1, Geometry, Algebra 2, Introductory Statistics, and AP¨_ Statistics. Today he's hard at work creating new exercises and articles for AP¨_ Statistics.
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[@Theswitchy1]

Statistics shreds my mind

[@edsknife]

*AP Stats Says it in the title XD Feels like AP, TBH

[@angelvanhoose8458]

ME TOO

[@oneilanelson9231]

Agree but I am determine to learn it. Especially since I need it for my degree and career path

[@Theswitchy1]

@@oneilanelson9231 welp turns out I ended up doing pretty well in my class haha. It's just one of those things that just clicks eventually. Keep at it, you got it!

[@jo.la796]

@@Theswitchy1 I took AP stats last year and now I am in college taking Applied Statistics (a jr year level course) and I lowkey miss these old stats days! Now I am just looking back at these notes because I forgot some stuff sadly.

[@chancyleang1156]

So my professor sucks at explaining things! Now, you’re officially my professor this semester LOL

[@starboyxayy]

Your professor I’m in 9th grade😩

[@hellokittyasf7274]

@@starboyxayy bro i’m in 8th😭😭

[@hawks9142]

Isn't that how it goes for all classes lol

[@MemeGang420]

Can't believe my teacher gave us *30* sets of data, and asked to calculate the correlation coefficient by hand. What an absolute @#&!

[@antipatiko]

i would actually write that as ... what an l@$$l

[@particleman5893]

lol just program a computer to do it

[@memz_4501]

Why dont you snap away your answers

[@probablymatthew]

How does this one guy know so much

[@furbalicious7349]

Matthew Barber big brain

[@MemeGang420]

Matthew Barber because coronavirus

[@piedotnet]

@@MemeGang420 yes

[@gameofvelets6421]

@Thanos yes

[@kayla1255]

This helped me understand what to do, but my teacher gave me way more than 4 numbers to calculate. It's going to take all day :(

[@estebanmoyer5938]

this man's voice is somehow soothing

[@yaminikathuria6077]

Thank you so much for explaining so simple and accurate

[@gavinmartin8586]

I honestly have to say. This dude is the smartest guy I have ever see. Like legit.

[@mpholekhehle5674]

This really helped me to understand my work better.

[@ayonsaha7963]

perfectly explained, thank you very much!

[@serenityalii7503]

I came to this video like 3 times and I still don’t get it💀

[@SMULGUM]

You just dumb ngl

[@iangarza990]

whatd you get on the ap test

[@anevandyk2]

So thankful for this video!

[@madinahazizi4463]

Awesome explanation! Thank you.

[@anthnyalxndr]

Explaining correlation in terms of z-scores is super helpful thank you 🙏

[@Prssur]

Glory to God this guy is blessing my life!!!

[@ThePavelkomin]

So good! Thanks!

[@lunarpunk2380]

I finally understand r-score! Thank you thank you thank you!!!!! I have a test in 2 days on this and it finally clicks

[@hafizhahazzakiyyah2740]

Thank you so much for explaining so simple and accurate. Hello, greetings from undip college student

[@everclara2061]

This all goes over my head, every time I watch/read

[@danielgladish2502]

Great video! Thanks sal!

[@benitareatlegile6516]

Hello Sir, How do we calculate correlation for polynomials...?

[@francescos7361]

Thanks I love statistic.

[@HeadRecieverAtHeadOffice]

The line should actually go through the mean and the intersections of the standard deviation lines right?

[@110Turab]

Thanks

[@Americabeatz]

this is mind blowing

[@dianeyin8987]

This couldn’t be more helpful.

[@SportsManVegetal]

What is the intuition behind (2,3) having a negative contribution to R?

[@azziecruz9355]

thanks fam

[@aftabsarwar4917]

Kindly tell the factors which affect coefficient correlation

[@JohaerJilani]

can u make videos on calculus based statistics and calculus based physics

[@lucasm4299]

Johaer Jilani I would really love Calculus based statistics. It's way more fun. Instead of adding a bunch of rectangles under a density curve, let's integrate.

[@user-xv7cs5hu1s]

I didnt understand why we used z scores to calculate the correlation coefficient. Can someone explain?

[@wiitennisace1340]

I hope the math quiz gets delayed somehow

[@buigley]

why you multiply Zxi*Zyi?

[@ominousreeve1447]

what is the e thing?

[@farmrocket_]

Is the correlation coefficient r also known as the slope of the line of best fit? Or is line of best fit something else?

[@violethaqueify]

I think “best fit” is something called Regression line. The difference between r correlation and regression line is that regression line requires an explanatory and a response variable to be calculated. The r correlation don’t require those variables to be calculated. (I’ve only been taking ap stats for a couple months so I’m not sure if I’m entirely right) sorry for the late reply haha.

[@lizla1964]

Can you explain how is 2/3 = 0.816?

[@HarvestingThings]

I'm so confused tho because my professor gave a COMPLETELY different formula for correlation coefficient; r=(meanx)(Z score of y)

[@maria-goretti2794]

Simply explained "I'm happy there are only 4 pairs here"... hahaha... Calculating repetitive stuffs manually can be tiring

[@louismaugard6272]

but how to calculate Sx and Yx ?

[@vkei3505]

To calculate Sx or Sy, you need to calculate the variance for both X and Y, then you calculate standard deviation, in our case Sx and Sy.

[@boatraft]

Sx is calculated at about 1:35, and he has other videos about standard deviation if you need more in-depth help with it.

[@lmackey63]

the cross bar is distractiong

[@KickOffSermons]

Now if I'm being asked to test for hypothesis

[@DanielGonzalez-wx9cg]

How did he get r=1/3

[@roseb2105]

in the book they dont divide by n-1 for variance

[@mafs5150]

it depends. for population, they use N. If they use sample, they use n-1

[@sarahahmed2847]

Ok I am confused that how he took out standard deviation of x ? Like HOW?!! SOMEONE HELP!!!

[@justinli19901027]

Why is r always between -1 and 1? I know that this question has been asked before but the answers are either too technical or too naive. Could someone please provide an answer that is mathematical in nature but can be understood by someone who have ok but not strong mathematical foundation. Thanks for your help.

[@benji4226]

-1 is the weakest correlation coefficient and 1 is the strongest correlation coefficient. Its like a rating of how strong/weak it is. I am a bit late though sorry.

[@oneilanelson9231]

@@benji4226 lol, a bit? Thanks though you just help me. I like reading comments. I saw a question before this that's 2 yrs old too but said to myself, "its too late to answer", then it hit me, someone else could benefit. Then I say you replying to a 2yr old question. What are the odds?

[@benji4226]

Oneila Nelson i answered the question just in case because, you never know.

[@AndWk]

Didn’t he get the wrong answer because he forgot to add the 1 at 6:02

[@kinanradaideh5479]

oh.

[@myriii201]

yeah I give up I don't understand it

[@juanuribe2968]

to confusing

[@markdavidalberto1712]

r situation hahahahaah

[@TheGozeraye]

Booooooooo, give us the black background

[@edsknife]

For last-minute, late-night studying XD Might as well use dark theme 24/7 tho

[@blossomdumdum]

This method gave me the wrong answer 💀

[@SMULGUM]

You just dumb ngl

[@Ulmasbek-th2hb]

not good honestly