StatQuest: PCA main ideas in only 5 minutes!!!

The main ideas behind PCA are actually super simple and that means it's easy to interpret a PCA plot: Samples that are correlated will cluster together apart from samples that are not correlated with them. In this video, I walk through the ideas so that you will have an intuitive sense of how PCA plots are draw. If you'd like more details, check out my full length PCA video here: • Principal Component An...
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0:00 Awesome song and introduction
0:27 Motivation for using PCA
1:23 Correlations among samples
3:36 PCA converts correlations into a 2-D graph
4:26 Interpreting PCA plots
5:08 Other options for dimension reduction
#statquest #PCA #ML

[@statquest]

Support StatQuest by buying my book The StatQuest Illustrated Guide to Machine Learning or a Study Guide or Merch!!! statquest.org/statquest-store/
Special thanks to PROTIST for the Russian subtitles!!! :)

[@falaksingla6242]

Hi Josh,
Love your content. Has helped me to learn a lot & grow. You are doing an awesome work. Please continue to do so.
Wanted to support you but unfortunately your Paypal link seems to be dysfunctional. Please update it.

[@tuongminhquoc]

I appreciated your effort spent on these videos. Sadly, since I am still a student, I have no money to support you just a bit. So, I have spent much of my effort to translate your videos into my language as it is my best language as a thank to you. Hope you would accept my thank.

[@statquest]

Thank you very much!!!! :)

[@tuongminhquoc]

@StatQuest with Josh Starmer I didn't think you would check this that soon :))) thanks for accepting my contribution!. I'll translate more of your videos whenever I have free time (and wifi haha :D )

[@statquest]

@@tuongminhquoc I really appreciate it! :)

[@leonguyen1204]

No wonder the subtitle was spot on! Great work mate, thanks for that! Also thanks @StatQuest with Josh Starmer, nice video with simple explanation, I'm trying to make sense of it.

[@ngoctandang9307]

Really excited when watching this video in Vietnamese subtitle, thank you!!!

[@fartissimo]

I enjoy your videos and you are performing a valuable service. The few things I would mention that would be helpful are that PCA is really a measure of covariance in a sample and that PCA does NOT provide ANY indication of statistical significance. Understanding Covariance is helpful to really understand PCA. Also, PCA is particularly useful when patterns emerge between experimental and non-experimental parameters. If patterns associated with experimental parameters are observed (i.e. treatment conditions) it indicates that there may be changes between samples/populations that are of interest; in cases where there are patterns associated with non-experimental parameters (such as collection date or incubation conditions) it indicates that the date of collection resulted in more variance than experimental parameters. In such a case, it points to a possible flaw in experimental design so that it would be of benefit to re-evaluate sample collection/preparation/incubation etc... in the workflows to minimize the influence on the studied populations.

[@guandongkou178]

Thank you Josh for the clearly explained abstract concepts! It is even more informational than a 2-hour lecture in a college.

[@statquest]

Glad it was helpful!

[@chintanchawda9725]

Every maths prof. must be like, way of explaination is as simple as possible. Thank you.

[@rorals4814]

Your voice tone reflects how confident and smart you are... Thanks, plz we need more videos related to machine learning stuff

[@HoriBar993]

You have a teaching talent.
Thank you for the all your videos!

[@Lastmomenttuitions]

Very nicely explained thank you so much for Putting this

[@statquest]

Hooray! I'm glad you like it. :)

[@aborucu]

This is by far the best on internet, Khan Academy doesnt have this content, all courses on coursera,udemy either wave formulas in the air or dont bother for a simple yet enlightening explanation..This is what practicioners need.Bravo!

[@statquest]

Thank you! :)

[@alondracortezenciso4272]

You just saved my life, sir! Doing journal club tomorrow and I had no idea how to read a PCA from steady-state metabolomics. Thank you!

[@statquest]

Glad I could help!

[@MeetPatel-jx6sn]

If my university would have been teaching 10% like you I would have completed my engineering in just 1year
Awesome video ♥

[@statquest]

Bam! :)

[@ohromujici]

Thanks! This was a great overview. I am in big data for a pharma company and we added PCA to one of our data tools. The documentation we received was a little "dry" so thank you for putting this into easy to understand key concepts. This helped a lot. Also, I did my original graduate work in mRNA decay so bonus points for dragging mRNA into this. :) :) :)

[@chriscollins5320]

What a great video that clearly and concisely explains PCA. Great job, keep these up.

[@sidekickwatson]

Thank you for these sequencing, singing, and recipe videos, this channel needs more subscribers.

[@statquest]

Thank you very much! :)

[@cynthiacabales22]

You are helping me survive my Research Analytics class - HOORAY! :-)

[@statquest]

BAM! :)

[@findingnemo4637]

100s of lines in 5 min.. great work sir.

[@zes7215]

wrg

[@kesialeite7913]

Thanks! Now I finally understand what I am doing in the lab! 🇧🇷

[@statquest]

Hooray! :)

[@robb8763]

so well structured, so on point - like all of the videos. very rare quality of a teacher: the comibnation of deep understanding AND the ability to narrow it down... almost like reducing dimensions to make things simpler to understand ;) what a great work!

[@statquest]

Thank you! :)

[@nourajamal8166]

This is one of the most great channels I have ever seen . If u are looking for a good ,easy and quick explanation you are in the right place ;)

[@statquest]

Wow, thanks!

[@anapeleteirovigil3199]

Came for the explanations and definitely stayed for the openings

[@statquest]

bam!

[@KingstonUponThames]

Best explanations of PCA in layman terms. Great work. Thank you!

[@statquest]

Wow, thanks!

[@jessefp1940]

Extremely helpful thanks, explaining the principal components in the order that you did, you nearly lost me I would consider rearranging the explanation of what pc1 and pc2 are in the video.

[@statquest]

Glad you liked this video! If you have time, you should check out the new and improved version (which is longer, but it's worth it, I promise you): ua-cam.com/video/FgakZw6K1QQ/v-deo.html

[@digigoliath]

Wow, this sheds a lot of light on dimension reduction. Very clearly explained & illustrated. TQVM!!!

[@statquest]

Thanks! :)

[@quililank]

I've been searching PCA for dummies for so long and I'm glad I found this! I can finally understand what the researchers in this journal I'm reading are trying to say Haha!

[@statquest]

Hooray!!! I'm so glad I could help. If you want to go a little bit deeper, let me recommend my other PCA video. If you watch that one, you will be a PCA master! ua-cam.com/video/FgakZw6K1QQ/v-deo.html

[@naturaldisastertv3298]

i was also having the same problem. i watched his 20 min video but I couldn't understand anything.

[@ZakLiTLearnfortheEnvironment]

I wanted to browse a video with the title ''HOW TO THANK STAT QUEST?" the only answer I got is just pray for the channel's success....

[@statquest]

Thank you! :)

[@adelutzaification]

Great video! I became a bit addicted to the StatQuest videos and my anxiety levels increased for a while, not seeing the usual morning Monday upload. Now I need to figure out what t-SNE plots are... ;)

[@Nicblocks]

I had to wrap my head around PCA plots as part of a presentation and just could not understand it. This was really well done and I'll be taking this knowledge in with me. Thank you!

[@statquest]

Hooray! :)

[@eemmmaaadd]

I always come across your videos when looking for stat information. And always your videos are the best.

[@statquest]

Awesome! :) Thank you! :)

[@luonhanquocvu8411]

As I learn PCA in a machine learning course, I knew that you have a good video explanation on this topic!! thanks!

[@statquest]

Glad it was helpful!

[@boundlessbrittany]

Holy moly. I finally understand the concept of PCA plots :O THANK YOU SO MUCH

[@statquest]

Bam! :)

[@marjanyaghoubi5729]

Hi sir, your explanation is very clear and vivid, I truly appreciate for it. Please do a video on Laplacian matrix and its application in dimension reduction.

[@verdasney]

It is more understandable that my 1.5 h lecture and a good start of PCA class.
Thank you for the video. Very well created.

[@statquest]

Glad it was helpful!

[@timlofton6595]

Good stuff Josh. Going to the lengthier version to further blast this through my thick skull. 😃 Appreciate your efforts with this!

[@statquest]

Enjoy!

[@edupazz]

Great!! Your Calm and crystal pronunciation makes the concept very clear to understand. Thanks

[@statquest]

Thank you!

[@liranzaidman1610]

2:03 People should stop here and listen very carefully because this is a really important concept, and I mean - Really important!
When analyzing data and the parameters effecting the outcome of something - this must be the way to think.
Great work

[@statquest]

Nice! :)

[@edsonwinnerify]

Thanks Josh, I can always get something new from your videos.

[@statquest]

bam! :)

[@wesleysbr]

Best regards from brazil, you are the best! thank you

[@noneoftheabove1589]

I love your humor! What a lovely way to present and explain. ahem.. what could be daunting to some lol (such as myself!) Grateful for the work and the passion! Keep up the good work!
A new subscriber!

[@statquest]

Thanks so much!

[@AbHiShEkdAS1505]

I have taken ML this semester and to be very honest I am understanding all the concepts from your videos. I would be really grateful if you could upload a playlist on Neural network and Deep Learning.

[@statquest]

Awesome! Neural Networks should come out in the next few months.

[@LorwaiTan]

@@statquest Thank you for so clearly explaining these concepts. Looking forward to your Neural Networks videos! Will share your videos with my colleagues.

[@sanathgunawardena832]

You're a lifesaver, Josh!
Thanks!

[@statquest]

Thanks!

[@juanno3581]

Thanks for the explanation!! It makes sense to use it with dendrograms for plant breeding!!

[@statquest]

BAM! :)

[@jorgepinto2241]

Excelent work! I love your video, It is so well explained. Thanks a lot!

[@amitrokade1140]

Finally understood it!
Thank You for a great video

[@naturaldisastertv3298]

i watched your 20 min video too. But this was easier to understand. Thank you so much.

[@statquest]

Hooray!

[@MM-qq6xp]

Excellent demonstration

[@menghongpor2667]

Thank you for all the videos. It is super easy to understand.

[@statquest]

Thanks! :)

[@fereidoon82]

well done, short and clean, thank u

[@UKFishCam]

Thank you so much for making this video! I've got my final year project due soon and Id lost the plot before this video!

[@statquest]

bam!

[@MeditaBrasil]

So well explained it!!! AMAZING!!! Thank you very much for making this video!!!

[@statquest]

Glad you enjoyed it!

[@arkadipbasu828]

Clearly explained Josh. Thank you

[@statquest]

Thank you!

[@newlifestartsnow4444]

Thanks for the video. What do the sizes and colours of the circles represent in the 3D scatter plot which appears around 2'47"? Are these just an aid for giving the plot depth?

[@andersonbessa9044]

Great explanation as always! Thanks a lot for your effort!

[@statquest]

Glad you liked it!

[@iftrejom]

The way you easily and calmly explain such complex topics is outstanding. Thank you very much.

[@statquest]

Thanks!

[@fredkiffer6753]

Thank you for existing!

[@statquest]

Thanks!

[@MrKB_SSJ2]

This was so smoothly explained. Thank you soooooooooooooooo much!!!!!

[@statquest]

Thanks!

[@mc9272]

StatQuest is really the best! that you so much to prevent my brain to explode!!!

[@statquest]

Thanks!

[@nompumelelongubane7579]

simple enough for my understanding. thanks a lot.

[@statquest]

Glad it helped!

[@jeremmoses8562]

You tech Harvard type of kind of stuff in elementary school way in all your videos, how do you that man! It's amazing, Thank you so much

[@statquest]

Thanks!

[@putriestimandasari4173]

I looovee your voice and your explanation... Great job, Sir.. Thank you !!!

[@statquest]

Hooray! I’m glad you like the video!! :)

[@MrUmban]

Excellent explanation! Thank you

[@statquest]

Thanks!

[@winniewu8581]

Thanks again. Good as always. Thanks for the weight and height example!

[@statquest]

Thank you! :)

[@SPeeDKiLL45]

Im so thankful for your videos bro !

[@statquest]

Glad you like them!

[@QuynhMata]

Phew, thank you so much! This was very helpful.

[@statquest]

Glad it helped!

[@SuperLameStuff]

Thank you for your clarity!

[@statquest]

Thanks!

[@ArtsIntentive]

WOW. YOUR EXPLANATIONS, MY GOOD MAN, WERE CLEAR.

[@statquest]

Thank you! :)

[@not1AM]

thanks man.. your videos are both very informative and fun.. really appreciated ❤❤❤❤❤❤

[@statquest]

Glad you like them!

[@kanefoster8780]

Great vid! Thanks

[@nadhirahbaharin.]

you need more subscribers!!! Thank you so much your videos are life saver

[@nadhirahbaharin.]

I didn't skip the ad to support you (it's the least I can do haha. )

[@DrATIF-ij9hy]

Thank you for the Arabic subtitling, as I have always recommended your channel to my students; best wishes.

[@statquest]

Thanks!

[@Mindyourbusiness0026]

StatQuest is the best

[@statquest]

Hooray!!! :)

[@96unicorns]

This was such a great explanation and so entertaining!

[@statquest]

Glad you enjoyed it!

[@xialinsang6403]

I really really enjoy your videos!!! Thank you so much !!!!

[@statquest]

Thank you! :)

[@Muuip]

Great concise presentation!
Much appreciated!👍

[@statquest]

Thanks!

[@Diegoblismartmedpengar]

oh man!! thank you, I needed this so bad

[@statquest]

:)

[@wildlifephoto7]

thank you for sharing your knowledge

[@statquest]

My pleasure!

[@rezaheydari3661]

thanks Josh your videos are amazing!!!

[@statquest]

Hooray! If you have time, check out the new PCA video that I made. It's longer, but it goes way deeper and it's just as easy to understand: ua-cam.com/video/FgakZw6K1QQ/v-deo.html

[@user-pw7hc6fd3h]

Such a beautiful work
Great video indeed
thanks !!

[@statquest]

Thank you! :)

[@giraldeaufagaerone4213]

thanks for these videos it helps me understand better compared to classes

[@statquest]

Thanks! :)

[@steveellison8686]

Dude, you are my hero. Thanks!

[@statquest]

bam!

[@riebeckita6798]

StatQuest is the best! Do you have any suggestions on how to do the last step: take clusters identified visually by PCA and clearly separate them? Particularly when they're not as cleanly clustered so discrimination becomes more subjective!

[@statquest]

It's a good question. You could try k-means clustering.

[@kadmielpereira]

Very insightful. Thanks!

[@statquest]

Glad it was helpful!

[@sridharmaloth87]

Thanks for keeping this video

[@laure189]

Fantastic video, thank you!

[@statquest]

Hooray! :)

[@tymothylim6550]

Thank you very much for this video! Really great video :)

[@statquest]

BAM!

[@lakep7798]

Wow--this was SO very helpful, even if corny at times, lol. Thank you so much!

[@statquest]

Thanks so much! :)

[@beshr1993]

This is EXCELLENT! Thank you good sir!

[@statquest]

Thank you! :)

[@Mochikoo]

Super helpful! Thank you!

[@statquest]

Awesome! :)

[@sanjaythumma7537]

Very well explained!

[@statquest]

Thanks! :)

[@vimalakirtilotus4611]

You have saved me from the sea of formulas. Thank you!

[@statquest]

bam!

[@MoMo-di5vy]

Thank you. This video is help me so many.

[@statquest]

Glad it was helpful!

[@isaac.jimenez.vega.]

Awesome video, thank you so much!

[@statquest]

Thanks!

[@nftk5413]

i love your way of explaining things tnx alot ...these videos are really helpful

[@statquest]

Glad you like them!

[@vanyabangera8299]

thank you so much... it is quite informative and understandable...

[@statquest]

Glad it was helpful!

[@jasonyimc]

love this content. Thanks!

[@statquest]

BAM! :)

[@trela47.]

Just want to let you know, the 'Awesome song' just won you a subscriber.

[@statquest]

Bam! :)

[@ahmedelbechir4870]

Great explination as always👍

[@statquest]

Thanks again!

[@tanaychowdhury1589]

These videos are Gold!!

[@statquest]

Thank you! :)

[@ZNMelowLeloNeka]

You just earned yourself a subscriber!!!!!

[@statquest]

bam!

[@robertobaldizon8206]

Very nice video. Thank you very much.

[@joaovaleriodesouzaneto8038]

As always very good!

[@statquest]

Thank you!