Hypothesis Testing and The Null Hypothesis, Clearly Explained!!!

One of the most basic concepts in statistics is hypothesis testing and something called The Null Hypothesis. This video breaks these concepts down into easy to understand pieces so that you can understand their motivation and their uses. By the time you're done with this video, Hypothesis Testing and the Null Hypothesis will be Clearly Explained!!!
NOTE: If you'd like to learn about The Alternative Hypothesis, check out...
• Alternative Hypotheses...
And if you'd like to learn about p-values, check out...
p-values: What they are and how to interpret them: • p-values: What they ar...
How to Calculate p-values: • How to calculate p-values
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0:00 Awesome song and introduction
0:22 Background
2:32 First hypothesis
4:09 Rejecting a hypothesis
4:40 Second hypothesis
7:14 Failing to reject a hypothesis
8:21 Rejecting vs Failing to Reject
9:01 Motivation for the Null Hypothesis
9:51 The Null Hypothesis
13:44 The next steps
Correction:
7:49 I meant to say Drug C instead of Drug A.
#StatQuest #NullHypothesis

[@statquest]

NOTE: At 7:49 I meant to say Drug C instead of Drug A. Support StatQuest by buying my book The StatQuest Illustrated Guide to Machine Learning or a Study Guide or Merch!!! statquest.org/statquest-store/

[@GauravSharma-ui4yd]

Hey josh i suggest you to write a book on everything you explained in your ML and prob&stats playlist. It will surely be a triple baaammm in the community. And also going to be best seller.

[@statquest]

One day I'll do that.

[@MrSmarthunky]

@@statquest We are waiting! :)

[@heplaysguitar1090]

@@GauravSharma-ui4yd Definitely, I was thinking the same, best seller without a doubt.

[@aspergale9836]

If only there was some nice feature to add quick, like, _annotations_ to videos to point out small stuff like that. Jeez, my hidden genius is scary =_= /s @KZbin

[@becca2239]

"I'm not going to name names", hilarious 🤣️

[@statquest]

:)

[@omkargowda5764]

@@statquest have you created a detailed video on inferential statistics ????? (•‿•)

[@statquest]

@@omkargowda5764 I believe this video would quality as a detailed video on inferential statistics.

[@crjacinro]

COVID 19

[@acruzp]

You know what I love about your channel Josh? You've made a real effort to get to the bottom of these concepts. It's beautiful to see such attention to detail and love for a subject.

[@statquest]

Wow, thank you!

[@miale3425]

Videos on platforms that require subscription fees are not even a tiny bit to your content 😂👏Thank you so much for the work!!

[@statquest]

Thank you very much! :)

[@88skewer]

really want to give you a big warm hug. You not only tought me these concept, now I am even confidence enough to explain these to someone else

[@statquest]

BAM! That is awesome.

[@arvind31459]

Josh doesn't accept hugs but BAMS!!

[@ThatDudeUKChronicles]

I literally watched your Statistics Fundamentals playlist in 2 days. It was too much of wisdom. I need to sit back, go through my notes again. Crazy crazy learning. Thank you so much for putting so many efforts that you made them look so effortless. Thank you, sir!

[@statquest]

BAM! :)

[@praneethsaitunuguntla7751]

I started my machine learning journey a week ago confused with all the math involved and I found a extremely understandable way here .Thank you John Starmer you are really great..

[@statquest]

Glad it was helpful!

[@Teawos98]

how is your journey going . Just started mine today

[@lucretiuscoleman8224]

yeah, how's it going? i think i'm halfway ready to apply for my first DS job

[@ab_intel5281]

My favorite hobby of the quarantine is to watch statquest and make notes. Very grateful to you Josh...

[@statquest]

bam!

[@MrRuhll]

really appreciate your work mate! all videos so well explained using a light speech. wish you the best

[@statquest]

Thank you very much! :)

[@mainulislam6765]

it just hit me that I laughed five times while learning statistics from this video. So far statistics lessons were about frowning and what not. BAM!!!

[@statquest]

Bam! :)

[@SaidakbarP]

Thank you Josh. This is a beautiful explanation. It goes to the very fundamentals of statistics with easy to understand examples. I have an upcoming data science interview, so I am refreshing my stat skills. Your channel is the best place to learn stats!

[@statquest]

Glad it was helpful!

[@abundant_AF]

Thank you, Josh! Great, simple introduction to hypothesis testing.

[@statquest]

Glad you liked it!

[@alexw31415]

Josh's voice is so cathartic to listen to and there's a perfect balance of learning at a great pace with minor sarcasm/banter that makes these videos so easy to binge and learn from. Thank you sir.

[@statquest]

Thank you so much! BAM! :)

[@alexw31415]

And I'm extra impressed to see that you read and respond to comments on 3-year-old videos! That's a lost art in the KZbin-verse. Double BAM!

[@actualBIAS]

Josh... and all of you friendly folks of the genetics department. Thank you guys SO MUCH for your great work. Thanks to you I learned so much in an intuitive way.

[@statquest]

bam! :)

[@RealSlimShady7]

For me, it has been StatQuest in the morning, afternoon, and night! This is Amazing!!! Who would have thought Stats and ML would be fun!! BAMMM! Thank you Josh :D

[@statquest]

Hooray!!! I'm glad you're enjoying StatQuest! :)

[@RealSlimShady7]

@@statquest All the time :)

[@rvvanani8252]

You're the Best.......It's like watching fun videos but in the end, we get amazing knowledge. Keep doing such amazing work.

[@statquest]

Thank you so much 😀

[@notme7310]

This is so good! Thank you so much! I tried watching other videos about this but none could explain it well as you do nor keep my attention long enough.

[@statquest]

Thank you!

[@thanhtrungnguyen4722]

amazing, start the day with StatQuest videos, so excited!

[@statquest]

Hooray!

[@leassis91]

thank you for taking all the time to explain the little things, it really helps!

[@statquest]

Thank you very much! :)

[@okonalbert]

This is the best statistics class I have ever been in, you break it down in a constructivist way, such that any rookie can understand

[@statquest]

Thank you!

[@Grillpander]

I've learned something today.

[@statquest]

Hooray! :)

[@sivaramakrishnanr3790]

@@statquest 000000⁰⁰⁰⁰⁰000⁰⁰⁰0⁰⁰0⁰0⁰0

[@NishantSewgobind]

Thank you for the wonderful and clear explanation! Very useful!

[@statquest]

Glad you enjoyed it!

[@ShermanSitter]

Great timing! Right after our discussion on NHST! :) ...another great video!

[@ShermanSitter]

PS. You probably already caught this, but I believe there is typo at 7:50 ("drug A", but meaning drug C?)

[@statquest]

Thanks for catching that. I added it to a pinned comment.

[@DrThalesAlexandre]

This is the best explanation on the null hypothesis I have seen so far.

[@statquest]

Thank you!

[@abhisheksaini1872]

Thank you sooooo much. You are a savior. The way you make complex things easy to understand is just amazing. Once again thank you so much ! :-))

[@statquest]

Glad it helped!

[@vikram90ful]

Thanks Josh, you made my day! thanks

[@statquest]

Hooray! :)

[@sonam2288]

Hello Sir, thank you so much for explaining it so well. The examples given by you makes is so easy for us understand it. You are amazing! Thank you 😊

[@statquest]

Thanks!

[@janbenedictsaldana6613]

Your videos really help me a lot. Thank you very much. I'll also be showing these videos to my students=)

[@statquest]

Awesome! :)

[@edmundchan8923]

Thanks you for the video. It always refreshes my mind

[@statquest]

Thank you! :)

[@rittikabose]

You have all the ways to make learning interesting and fun, even the kids will also feel like knowing Statistics now !!!

[@statquest]

Glad you think so!

[@rittikabose]

@@statquest Can you post some interview materials? It will be of great help. I attended an interview where I was asked about the different testing methods and KPIs based on different data situations.

[@statquest]

@@rittikabose I need people to send me their interview questions. Can you send me yours: statquest.org/contact/

[@alexey9624]

Of course like! Awesome lectures! Explained very clearly and easily - the best I found. Unfortunately, I did not find anything 'clearly explained' at the channel about Markov models.

[@statquest]

Markov Models are on the to-do list.

[@alexey9624]

Great! And is a theory of random processes on the list?

[@mc_v6237]

Your stat fundamental series realy helped me understand the basics of hypothesis testing, huge thanks for that! I searched for a video explaining the mathematical logic behind z and t test but found no one that realy explained the Details in an understandable way. Would you mabey consider making a video based on all the stuff you allready explained but connecting the dots and other neccecary details for z and t tests? Would be great if you'd think about it. (Unless you allready made one and I just didnt found it^^)

[@statquest]

You know, one day I would love to do a proper video on t-tests. For now, however, the only thing I have is a video that shows you that the logic behind t-tests is the same exact logic behind linear regression, which is also the same exact logic behind ANOVA and a bunch of other tests (some of which don't even have names). For details, first learn about linear regression... kzbin.info/www/bejne/pJyVdIR_idKSm9E and then learn how it naturally extends to t-tests... kzbin.info/www/bejne/hHeYkJWqhMZ2n8k

[@elsabetbogale7227]

i love this, i actually understand bless your heart

[@statquest]

Thanks!

[@bharanidharanbalu]

Thanks Mr Josh for the wonder video.... You are taking lots of effects to make the video....... your clarity of explanation is really good ..... possible do it for anomaly detection in time series ........Thanks a lot for making more videos.

[@statquest]

Thank you very much! :)

[@dillman4170]

Great Video! Very well explained. You are helping a lot of people

[@statquest]

Glad you think so!

[@karnaghose4784]

You explained better than my college lecturer

[@statquest]

Thanks!

[@lizshale4349]

i do learn a lot from you and enjoy much fun!!!Thank you Josh!!!!!!!!!!!!

[@statquest]

Awesome, thank you!

[@pranayshridhar9980]

your the best professor i ever had 👍

[@statquest]

Thanks! 😃

[@raj-nz4bj]

I am your fan . Great help in machine learning

[@statquest]

Thank you! :)

[@sachithgomes2672]

When Knowledge and Entertainment are found together in one place. 🤩

[@statquest]

bam! :)

[@virendrakumar-fx7se]

Every video of urs is really helpful to understand the concept..adding fun to teaching is really helpful.

[@statquest]

Thanks!

[@rishiraj8101]

wow! indeed clearly explained, Josh.

[@statquest]

Thank you! :)

[@vectors1970]

Finally found the god of statistics

[@statquest]

:)

[@swapnilchavan7076]

Thank you josh .... You are wonderfulllll😊

[@statquest]

Thank you very much! :)

[@yufeizhan726]

This is REALLY helpful.

[@statquest]

Thank you! :)

[@sombra145b]

Great video, thanks! I completely understand what you said about us only being able to reject or fail to reject the null hypothesis, but I have seen many published papers stating their main hypotheses to be "there is no difference between groups". They then state in the discussion "the results support our hypothesis" when the tests find no difference and claim that the intervention is equally helpful for different age groups, for example. Is this problematic? Should the peer review have said something? Should they have switched the null hypothesis and the alternative hypothesis somehow because the type I error becomes the type II error and vice versa? What would be the algorithm for doing such research when they want to prove that the intervention is as effective as the other one?

[@statquest]

Without knowing all of the details, I would say it is very odd to say that the main hypothesis is the null and that a large p-value supports that. The reason it's odd is that there could be a million reasons why the p-value was large, some of which have nothing to do with the treatment (for example, it could be that someone just wrote the data down incorrectly).

[@AnkurBhase]

I'll be honest. I watch your videos waiting for the BAM and forget to focus on the concept! Then I've to go back all over again! 😂😂😂

[@statquest]

BAM!

[@user-cc7fo5ml1m]

Thank you very much!

[@statquest]

You're welcome!

[@pradnya173]

You are such a cool teacher! Thank you

[@statquest]

Thank you! 😃!

[@gissellevargas3551]

You are the absolute best!

[@statquest]

Thank you very much! :)

[@maessonmlo]

Thanks for sharing this wonderful video. See you!

[@statquest]

Thanks!

[@hanshernandez5513]

Amazing videos! I just iked and subscribed double BAM!

[@statquest]

Hooray! Thank you! :)

[@thisisvickyge]

Really love your videos!!!

[@statquest]

Thank you! :)

[@fahimmahmud3115]

I so wish I could meet you in person. You are just great!

[@statquest]

Thanks!

[@wildboy747]

Jesus thank you man! I finally understand that null hypothesis it was tricky for me

[@statquest]

Bam! :)

[@archanatatavarti1951]

You're so good!

[@statquest]

Thank you! :)

[@nikitapatel9563]

After... Watching this video I feel relax.. that. I knw. Something.. clearly

[@statquest]

Hooray! :)

[@MrMertcam]

Thanks, now I mixed up all I have ever known about hypothesis!

[@statquest]

Does that mean that this video helped you understand hypothesis testing, or did it just make things more confusing?

[@gayathrikurada3315]

Hi Josh,Thank you for the awesome video :) I'm slightly confused on how to frame null hypothesis for a given statement. For eg :A pizza place claims that their delivery time is 30 minutes or less than that on an avg. Now our null hypothesis will be "The delivery time is NOT less than or equal to 30 mins that is basically greater than 30 mins." Is this correct ?

[@statquest]

Yes.

[@angelalebenglik5538]

Hello! Do you think that I could get a basic notion of inferential statistics after watching the whole "Statistics Fundamentals" videos? If not, which ones do you recommend me to watch? :) BTW this videos changed my belief that I could actually understand something with numbers involved

[@statquest]

Yes, I think you could get a good sense of what inferential statistics is and what you can do with it from my videos. Glad my videos are helpful!

[@maxjohnson7623]

thank you so much for your videos

[@statquest]

Thank you!

[@afihaileywibowo1095]

You know, I'm going to learn the chords of that cute intro! 😊

[@statquest]

C, Aminor, G, C. BAM! :) (NOTE: They might sound a little different played on a normal guitar. The notes will be the same, but the order they are played might be different.)

[@tawiwutcharuwat8999]

Thank you so much!

[@statquest]

You're welcome!

[@gabrielrivetti3064]

The hypothesis testing and confidence intervals that we estimate from a sample and generalize to a population is an inductive process. However, the internal procedure of these statistical processes is deductive, as we make several assumptions and then deduce our conclusions, right?

[@ishitaarora281]

your intros are the best

[@statquest]

Thanks!

[@amoghbharadwaj9252]

Hello Josh, thank you so much for the brilliant video :) I have a question related to Hypothesis testing. How is hypothesis testing used in the data science industry ? can you give me a couple of use cases? Like, say If I am solving a business problem, and I have 30 features and a target variable. do I use hypothesis testing to check if the relationship between any 2 variables is significant or not? like that am I doing hypothesis testing for all the trends/patterns observed during feature engineering to check if the relationship is due to random choice or if it really exists? I was just thinking about the bigger picture in the industry, please let me know, thank you :)

[@statquest]

A/B testing is all about hypothesis testing. So there's one industry use case. Hypothesis testing can also be used to determine if your machine learning model is overfit to the data.

[@esther1994]

Thank you very much.

[@statquest]

:)

[@shubhamkalra1234]

Hello, that's a great video! Could you please tell me the software that you use to create such animated videos? Thank you.

[@statquest]

I use Keynote and iMovie.

[@HalfHotHalfCold]

Using your page as a review for a job interview

[@statquest]

Good luck! :)

[@pingyang6385]

HI, @josh, i watched all your stat videos, they are indeed veery good and very clear. I am wondering whether you have related notes or ppt for sharing. thank you!

[@statquest]

I have study guides for some of my videos here: statquest.org/studyguides/

[@sriramcharan180]

Excellent explanation

[@statquest]

Glad you think so!

[@istwishmeister9368]

Hi Josh, This was awesome. But, can you please make some video regarding GCN(Graph Convolution Network) in future? It would be nice to get some explanation from your perspective.

[@statquest]

I'll keep that in mind.

[@himankaghosh7307]

Great concept explanation

[@statquest]

Glad you liked it!

[@Norainjoe]

Hilarious! I've never lol'd on a stats video before

[@statquest]

Bam! :)

[@HPEKASHP]

Hi Josh, thanks for your amazing channel :D I need help with something, I've made a campaign. So there are the group of people who were impacted by the campaign and bought, the people who were impacted and didn't buy, and the group of people who weren't impacted and still buy, and the one that either was impacted and bought. I want to know if the difference between, impacted group and non impacted is significant? How do I conceive the null hypothesis? Thanks a lot

[@statquest]

The null is that there is no difference. You can then use Fisher's Exact test (or chi-square) to determine if there is: kzbin.info/www/bejne/q5XccqmslrKdnK8

[@Technolance]

Good Job!

[@statquest]

Thank you! :)

[@neuodev]

Triple Bam 💥 !! Awesome Video for hypthesis testing

[@statquest]

Thanks!

[@arandhir]

This is awesome...can u please make video on Skewness and Kurtosis ... explaining it's concept and practical application.... Thanks in advance for reply

[@statquest]

I'll keep it in mind.

[@viduradias4646]

Thank you!!

[@statquest]

:)

[@sarahussein7616]

Your channel is so bammm 🔥🔥❤️

[@statquest]

bam! :)

[@MrSmarthunky]

Very good video Mr.Starmer. One basic question: Why can't the null hypothesis be : There is a difference between Drug C and Drug D? Any things should I have to consider while formulating my hypothesis?

[@statquest]

Due to random things, like exercise, age, etc, if we give the exact same drug to two groups of people, the mean recovery times for the two groups will probably be a little different. So, if we want the null hypothesis to be that there is a difference between two drugs, we have to quantify how big that difference is, because there will probably be a small difference in the means even if both groups take the exact same drug. So we could test that the difference between drugs is 12 hours, or 13 hours, or 11 hours, but how do we decide? Since we can't decide very easily, we set the null hypothesis to be that the difference is 0. Then we can test to see if the results are significantly different from 0. If so, then there is probably a difference between the two drugs.

[@karangadgil9847]

made it so easy to comprehend

[@statquest]

Thanks!

[@aryananand5089]

Literally I have an exam tomorrow. You’ve been a lifesaver!

[@statquest]

Good luck! :)

[@-why6039]

Me seeing this comment a night before my exam: 👁👄👁 same bruh (ik it’s late reply but whatever)

[@aryananand5089]

@@-why6039 hahaha i get it :,)

[@-why6039]

@@aryananand5089 ikr! Statistics is 😭

[@aryananand5089]

@@-why6039 all the best! 😊✨

[@arjundebnath78]

At 4 min 15 sec , when you say the experiment is conducted multiple times , is it done on the same group of people? or different.

[@mdabdullahalhasib1730]

Lovely BAM!!!!! from Bangladesh...

[@statquest]

Thanks!

[@albertocaruso6968]

Sei veramente bravo, you are very smart. Thanks!

[@statquest]

Grazie! :)

[@aaminaafshan240]

Thank you!

[@statquest]

You're welcome!

[@jennyfu720]

thanks for this video

[@statquest]

Thanks!

[@santoshgujar5237]

Thank you, Sir

[@statquest]

Bam! :)

[@oguve278]

Thanks for the Great Video! Would it still be considered a Null Hypothesis if it was phrased “People taking Drug C do not need fewer hours to recover than those who take Drug D” ?

[@statquest]

Yes, that would be called a "one-sided test". However, generally speaking, one sided tests are more trouble than they are worth.

[@alecvan7143]

great vid :)

[@statquest]

Thank you! :)

[@lauraliu2996]

The reason I always click your video is just because I want to hear you singing

[@statquest]

You have great taste in singing! :)

[@dante911ify]

Great video however, I have a question. Throughtout the video, you used the phrase "random differences" for factors like Better diet, more exercise, (or may be some genetic mutation) which affect recovery time but are these factors really random ? These factors may be unknown to the experimenter but is it a good idea to consider them random ? I mean the phrase "Drug A may perform better than Drug B due to chance" doesn't make sense considering there would be deterministic reasons with mechanical explanations which would explain the action of the drugs

[@statquest]

I agree, statisticians use words like "random" and "error" in strange ways. However, in the language of statistics, "random" means "things we didn't factor into the model". Unfortunately, that's just the way they use the term and there's not much we can do about it.

[@dante911ify]

@@statquest thank you for the answer

[@haneulkim4902]

Thanks Josh! When we fail to reject Null Hypothesis (No difference in recovery time between two drugs) can we conclude that statement in Null hypothesis is true i.e. No difference in recovery time between two drug?

[@statquest]

I believe I answer this question at 8:21

[@mintsss872]

I love the songs that are at the start of every video

[@statquest]

Thank you!

[@hungariantornado]

thank you!!!

[@statquest]

:)

[@jiinglesgreen3869]

Woh man, great content.

[@statquest]

Thanks!

[@rhamz8880]

Nice im no longer confused.

[@statquest]

bam!

[@ThomasHaberkorn]

How many experiments should there be to be confident in rejecting/failing to reject the null hypothesis?

[@statquest]

There are ways to determine the number of experiments needed and I describe them in these videos: kzbin.info/www/bejne/iKTGZq2krLdofKM and kzbin.info/www/bejne/jInCfmaqft6cj80

[@damini007]

Thank you so muchh:)

[@statquest]

Thanks!