P-value in statistics: Understanding the p-value and what it tells us - Statistics Help

This video explains how to use the p-value to draw conclusions from statistical output. Try the quiz after: • p-values - a quiz to d...
This video includes the story of Helen, making sure that the choconutties she sells have sufficient peanuts.
0:00 Introduction
0:17 Formal and informal definitions
0:36 Example - Helen's choconutties
1:03 Null hypothesis
1:19 Alternative hypothesis
1:36 Significance level
1:46 Sample and analysis
2:40 Interpretation
3:10 Not rejecting the null
3:30 Summary
3:50 Small p-value means significant result.
4:33 Disclaimer
If you would like more about where the p-value comes from, take a look at "Understanding where the p-value comes from": • P-value calculations: ...
For a step-by-step description of how to use a p-value in a hypothesis test, see our video Hypothesis Testing: • Hypothesis testing: st...
For a quiz to further develop your understanding of a p-value see: • p-values - a quiz to d...
See creativemaths.net/videos/ for all of Dr Nic's videos organised by topic.
#DrNicStats #Statistics

[@pavanifernando4504]

The best thing I've ever heard "if P is low, Null must go" This is golden!

[@DrNic]

I agree. I didn’t make it up and tried to credit whoever did, but couldn’t find out. So helpful!

[@emadharazi5044]

Fair of you to throw in the disclaimer but that was really well explained. "If you can't explain it simply, you don't understand it well enough" - Einstein.

[@chakravarthyn1]

The simplest explanation I have found in the internet. Avoiding the jargon made this very easy to understand. Two thumbs up!!

[@KommentarSpaltenKrieger]

I agree but has it been dumbed down so much that it actually doesn't tell the truth anymore? This is my biggest worry with easy explanations for sophisticated phenomena.

[@garmarianne3533]

@@KommentarSpaltenKrieger how come p-value is a sophisticated phenomena?

[@KommentarSpaltenKrieger]

@@garmarianne3533 it certainly requires an understanding of statistics. I don't know about you, but the first time I encountered statistics was during university.

[@garmarianne3533]

@@KommentarSpaltenKrieger It leads to understanding of satistics, it doesn't require it.

[@KommentarSpaltenKrieger]

@@garmarianne3533 But I don't understand p if I don't understand statistics. I have to accept p and whatever is told me about p, but I don't know why p is the value which tells me that a finding is most likely not due to randomness. It's the difference between understanding a thing and acousmatics.

[@SamuelNathanuelson]

The p-value is used to determine if the outcome of an experiment is statistically significant. A low p-value means that, assuming the null hypothesis is true, there is a very low likelihood that this outcome was a result of luck. A high p-value means that, assuming the null hypothesis is true, this outcome was very likely.

[@sanderustrup1842]

That's a nice way to break it down, thanks Eliot!

[@mayzhou3534]

but how many are low, is it should below 0.5?

[@AmeerulIslam]

A low p-value means that, assuming the null hypothesis is true (or you mean false) ?

[@Kay-zo3wl]

what is null hypothesis

[@jishanzaman3421]

Your explanation is more easier than this video ❤️❤️

[@fordros]

This video absolutely saved me on my exam today. Thank you. People like you are amazing

[@christaolson]

Love this :) Needed a quick refresher on p-values and got it without dying of boredom or wading through overly complicated definitions. Funny, simple, educational. Thanks!

[@adryanneparker190]

0:40 Helen?? No. That's Mello from Death Note. That's not Helen.

[@DrNic]

Adryanne Parker Maybe... (Blame my editor)

[@memjaym]

+Adryanne Parker LOL xD

[@labbiqaahmed4620]

lol

[@venugopal4359]

YEAH MELLO ALL THE WAY!!!

[@thenormalpotato8451]

Adryanne Parker I nearly screamed when my teacher showed this to our class, haha!

[@DrNic]

I'm happy to hear that. Life-saving is a good thing.

[@Jonesy795]

Thank you for making statistics easy to follow in an entertaining way! You definitely help students like me who have difficulty following the concepts...your method of teaching works perfect for me b/c it helps me get it! I appreciate how your videos simplify the explanations so that its easy to follow. Thank you!

[@wewung2]

"P is low, Null must go" love it!

[@DrNic]

We are so glad you like it. Statistics is such an important subject that it needs to be fun as well.

[@carlosfernandez5833]

"In general, ..." That was my favorite part LOL.

[@DrNic]

The alpha value can be decided ahead of time, and is really a remnant of the days when p-values were hard to calculate. You would decide on an alpha value and then find out the cutoff for the statistic you were measuring. These days we have p-values so can see from them how much evidence there is that the null hypothesis is false. An alpha value of 0.05 or 5% is the most usual, but it is arbitrary. The alpha value is also interpreted as the probability of making a type I error, which is rejecting the null hypothesis when you shouldn't.

[@umakegoodcookies]

This could not be more incorrect (and is now repeated in a number of terrible stats textbooks). In order to calculate the p-value you're deriving it from an assumption that the null hypothesis is true. But the p-value is uniformly distributed when the null hypothesis is true which means all of them, .05, .5, .0001, are equally likely to occur and are not, in and of themselves, evidence of the effect. Without stating beforehand some sort of cutoff you're just like the person who stumbles across something odd and calls it a surprising finding. I liked Feynman's little story that starts with him talking about this amazing license plate number he stumbled upon in the parking lot when walking into class. The video already has issues arguing that p-values are measures of evidence, an idea that even Fisher gave up on later in his career (thus likelihood ratios).

[@rocketrider1405]

plus you should be selecting your alpha level a-priori which means before you do anything

[@DrNic]

Thank you for your encouragement. I hope you don't mind, but I quoted you in my blog. Comments like these really make my day.

[@oladog]

The most simple and easy to understand explanation I have found. Thanks.

[@matthewwroblewski8752]

The animations crack me up. Fun video. Thanks.

[@hengchunsong301]

Thank you so much for explaining this concept in such understandable fashion!

[@malvikachandhok8571]

I love how innovative your videos are! Please make more of them, I can't wait to finish some more playlists :D These are amazing and thank you so much for all your explanation!

[@DrNic]

Glad you like them!

[@romidanika]

best video ever! i would love all my classes would be as simple as this for better understanding, great job congrats!

[@Yingzs]

This is really helpful!! I finally get the idea of p-value after watching this video. Thanks for making this video :)

[@DrNic]

Thanks. Helen has taken on a life of her own over the years.

[@SteveOvsFidel]

If you're here to quickly and easily understand the concept of P-values, then you've found the right video. Good on you, Dr. Nic.

[@DrNic]

That is good to hear. I think it works best if you already have some idea of what a p-value is, but it isn't clear.

[@seoyoonkim9841]

This is by far the best tutorial out there in terms of p-value. Thank you so much you just saved my life.

[@DrNic]

Glad it helped!

[@sophiedornan6583]

This is excellent! I have been trying to get this stuff down all year at uni and it's been going in one ear and out the other. Your video really helped! Thanks :)

[@0nullnil]

Mello survived, changed his name to Helen and owns a chocolate business, lmao. Matt pretends to be his brother too.

[@DrNic]

I can neither confirm nor deny the presence of Mello in these videos. ;)

[@0nullnil]

I mean regardless the association is there. **shrugs**

[@yeetusdeletus1229]

@@0nullnil lol imagine in the new one shot from this year with 27 year old Near it showed 29 yr old Mello and Matt owning a chocolate company

[@0nullnil]

@@yeetusdeletus1229 I’m imagining it and honestly I feel like that could happen..

[@emmatheenigma6939]

Omg I'm not the only one who thought it looked like Mello

[@allisonfernandez7941]

This video explains p-values and significance levels really well. Thanks!

[@inv8890]

my goodness... you explained it too damn clearly. I have been looking all over youtube.. for a good explanation.

[@TheBaam100]

Thank you so much for this great, funny and simple explanation. You just saved me hours of trying to understand this concept :)

[@lilycallaghan1245]

Thank you!! Your video was such a great help for a refresher on the course. :)

[@afonsovale7799]

Purely amazing explanation, simple, effective, clear and with a touch of humour. Great video :)

[@DrNic]

Glad you enjoyed it! That is exactly what we are aiming for.

[@Fiddler104]

Dr. Nic - thank you! We truly need more teachers like you.

[@DrNic]

You're very welcome!

[@mohammedamayri2237]

Honestly those videos are the only reason i still have hope on this subject. The comedy in the presentation is just the cherry on the top.

[@DrNic]

That is so good to hear. I love that my videos keep helping people.

[@mintwinter9655]

I liked purely because I saw Mellow. I also clicked the video because I saw Mellow. You can denie it all you want but that is Mellow from death note.

[@ahahahahah650]

This is by far the best video concerning p-value. Amazing job

[@DrNic]

Wow, thanks!

[@kaushilkundalia2197]

Such a clear explaination ! Thank you a lot :D !

[@lukepretorius8395]

That was an excellent explanation - thanks!

[@elizabethn9484]

Watching this has made a huge difference to my understanding of p-values, I was struggling to grasp the concept but your content has explained it perfectly. Thank you!

[@DrNic]

Glad it helped!

[@jaggyjut]

This is by far the best video on explaining p-value. Thank you.

[@DrNic]

Glad it was helpful!

[@divyamarkande35]

Very basic and essential concept of Statistical Sciences explained in a very very easy language, thank you, SLC. .

[@promitananyochakraborty6800]

One of the best channels I have bumped into so far. Way better than Khan Academy, I must say!

[@devpatel4087]

The perfect video! I don't understand why college makes it sound like a concept of god; it's simple: if p is low, the null must go! Thank you!

[@DrNic]

Thank you for that. p-value is one of those things that make no sense until you understand them, but once you do, you wonder what the problem was. Glad I could help.

[@hayesjennife]

Thank Helen I am beyond the eleventh hour trying to understand Null Hypotheses and p values for college all the while battling Breast Cancer. Your video has made my life soooo less stressful. Hopefully I can submit my stuff as the research project is past due, and get to bed at a decent hour...keep em coming. I have another Data Analysis course this summer I will be looking out for more of your videos. Thank you for making it so simplistic...not every one is a math genuis:) You Rock

[@rickd438]

I hope you are ok, health wise.

[@MeetYourArchitect]

get well soon :)

[@za356]

How are you doing now Jennifer?

[@hayesjennife]

Zaχ I’m doing well. Thank you for asking

[@kt.stokoe]

Pray for your recovery. God is good! Math is amazing.. once you understand it. Wishing you all the best for your studying and health journey x

[@niteshmaruthi8784]

This is an excellent video. Thank you!!

[@ilmctmp]

Short and sweet. Thanks for the lucid explanation

[@DrNic]

Glad it was helpful!

[@4635683763]

watched it again and i can safely say you may have scored me a neat 15% in my test this evening, Helen is awesome! :)

[@calinagoia4911]

Wonderful explained!! Those wonderful people who take from their time in order to help others.. God bless you!

[@DrNic]

Thank you Calina. Do tell your friends, as we do get a little bit of money from advertising to help us keep going.

[@wnapholi]

Excellent video. Very helpful. Thank you

[@Jesh191]

Thank you. I finally understand what p-value means.

[@P1A2T34]

I liked your disclaimer, made me smile. Cool animations too.

[@pacificswell]

Yes, love this simple explanation!

[@Abeer_Al]

Extremely helpful n understandable.

[@hammadmohammedosman4984]

This is really awesome , Applause from Egypt 😃👌👍👏👏👏👏👏👏👏

[@chauphamminh1121]

Great video ! It actually helped me a lot. Just subscribed the channel. Keep up the good work. Thanks.

[@bethanyborden7331]

Your videos are really saving my butt, they're so clear and concise and also I love the art, the facial expressions always get me haha, it really helps me to stay engaged!

[@DrNic]

Thanks Bethany - that is great to hear. Mission accomplished!

[@lisama2748]

Omg after a dozens of video and lectures I finally get it form this vid... this is the perfect example guys...

[@DrNic]

Happy to hear it

[@Hahahahahahahahasiu]

I need to say thank you Dr.Nic Because currently I am undergraduate student from science school. My dream is to being a scientist ,however my statistics. is so bad,but.after watch the video ,I find my passion to pickup and overcome statistics !!!! So,Thank you so much for making this video.Hope we can learn more from you in the future day!!

[@DrNic]

That is great to hear that I can help you reach your dream. I have videos to help people know how to study for statistics as well. You can find them all laid out nicely here: creativemaths.net/videos/

[@lad812]

I love your video series and show it to my college students!

[@bibatoo]

thank you so very much for this helpful explanation...

[@chantalebianco8202]

Omg thank you for this!! We need more dumbed down videos like yours!!!

[@EmRatHien]

Amazing explanations!

[@ShamaAkberallyClass]

Excellent explanation! So simple and easy to understand. Thank you for this!

[@DrNic]

You are most welcome

[@katb3621]

ahhh the perils of Helen and her choconutties continue!! I love these videos thank you so much! Reminds me of Andy Fields stats book! Awesome information.

[@jff711]

Thank you, I really liked the explanation!

[@masterchief9064]

Wow this was a very helpful video, animations are great!

[@orpat007]

Very good explanation! Understood in under 10 mins with multiple replays.

[@DrNic]

That is great to hear. It is really sensible to watch it several times, and pause and think.

[@JB-nw4ef]

Great video! Helped me a lot!

[@irfanjpj]

Really Great methodology of teaching. I would give more than one likes if i could. Thank you dear Miss!

[@causa04]

great video... thanks!!! this is a perfect video on how to put statistic concepts in practice =)

[@chelsea2750]

greatest video ever! finally got the concept of p-value clear

[@DrNic]

Wow that is high praise

[@OliverAyto]

Great video - perfect for getting the concept in my head. Great jokes too :D

[@DrNic]

Glad you enjoyed it. Our editor is pretty funny.

[@sally-annesinclair8405]

Great example! Thank you :)

[@DrNic]

Pleased to hear it. We do our best.

[@hassaananwar6212]

Wonderful explanation !!

[@fireheart__7]

Best video on p-value out there !! Thank you :)

[@DrNic]

Glad you think so!

[@naajix]

beautifully explained... thank you ma'am

[@ufo8mykat]

Brilliant, playful. Thank you!

[@TerryRajsombath]

Thanks a ton for clearing this up!

[@stephenday4834]

Thank you! Very well explained. Love the graphics

[@DrNic]

Glad you like them! There is a lot of work in them.

[@lemyul]

i enjoyed watching this, thanks!

[@andromedafrigga7653]

Thank you :) this helped me lots with completing my final paper. I have a hard time understanding stats

[@liloupirate]

Loving the animations

[@daniellecalder5193]

This is great! Thank you.

[@atpole818]

I enjoy your style of speaking. Definitely subscribing

[@psandbergnz]

After watching this video, I'm still clueless about p values and the "null hypothesis". The null hypothesis needs to be better explained and WHY a low p value implies rejection of the null hypothesis.

[@SR-mv2mf]

Paul Sandberg totally agree

[@daphneashba]

Null hypothesis means that you are testing your variables at 0.05 (%95 level) significance level your variables if they are correct to estimate your model or sample then youe variables is not equal to zero,they are affecting your sample which null hypothesis was Ho:B1=B2=0 this implies if you have right variables to solve your model then you reject null hypothesis because b1 and b2 has an effect on your model.p value determines your null hypothesis is really true or wrong.So if mean average of your variables more than 0.05 in p value than you have to accept that your variables are wrong and has no effect or your null is true.

[@kinguzi24]

Were you able to find an explanation to this confusion?

[@sierrasouthwell9237]

Someone correct me if I'm wrong. The null hypothesis is the assumption that every variation to expected results is due to chance. In this video, the assumption was that , on average, choconutties contained 70g of nuts. The difference between her sample mean and the expected mean is put through some complicated equations to get a t value. You use that t value to find the p value from a pre-made chart. The p value in this example was 0.18. That means that there is only an 18% probability that the difference between her sample nut-mean and the 70g nut-mean is due to chance. That means that there is a 72% chance that these results are NOT due to chance and she really doesn't have enough nuts in her chocolate bars. However, it is convention in statistics that we have to reach a 95% confidence level before we can reject the null hypothesis (our assumption that whatever observed events that differ from the norm are due to chance.) For example, if a scientist observes a series of really hot days in the middle of winter, he can take take a large sample of the temperature of these few days in the year across 50-75 years in the past. He then finds the average (mean) of the temperature. This is the expected. He subtracts the actual temperature from the expected, then finds the t and then p value. If the p value is 0.1, then there is a 10% chance that these few hot days are just happenstance. However, if the p value is 0.01, then there is only a 1% probability that these hot days are hotter than average due to chance. There is likely something causing these days to be hotter. By rejecting the null hypothesis, we're saying that these results are NOT due to random variation in the universe.

[@mlsivaprasad]

Completely agree with you

[@sigmabishop5212]

I love this channel 💕

[@breakdancerQ]

Lol Funny and simple way to explain it, very clear again!

[@maverick4me]

You just saved my life ,helping me wrap around this concept incidentally tend to be mathematically challenged

[@DrNic]

That is great to hear - I like to save lives!

[@flaviohenri7]

OMG these videos are hilarious, i loved it, and btw im learning a lot! Thank you!

[@ahmadhassan8560]

Wow loved it, i had watched many complicated explaination regarding it , it just untangled the data in my head. plus loved the animations.

[@DrNic]

Glad it helped!

[@DrNic]

Hi. I'm not sure what you are asking. It depends on which way you set up the null and alternative hypotheses. It often seems backwards, as we are trying to disprove something in order rather than prove it.

[@paritoshjain9537]

soooooo goood. very satifying. Was struggling from last 2 days. But now very sorted

[@DrNic]

I love to hear that.

[@massimobuonaiuto8753]

Great explanation and example. Thanks!!!

[@DrNic]

You are welcome

[@sachinthadahanayaka9061]

Great Video! Thanks.

[@luismoreyra6804]

Excelent video!! Super clear!! Bravo!!

[@DrNic]

Glad it was helpful!

[@faustin289]

This video moved my niddle of understanding P-value a notch closer to where I it to be.

[@DrNic]

That IS good news

[@Peek-a-berries]

accent is fine and the video is helpful! THANK YOU MADAME!

[@nso112]

Rad video! Needed some clarification on p-values and alpha values, it did the trick and made me laugh. Thanks! Will look for more of your vids.

[@nursesofyaalqahtaniy7424]

I am watching this 2020 how useful is this channel great work thank you doctor Nic's

[@DrNic]

Thanks for watching! The older videos still get a heap of views. It is most gratifying.

[@mps6934]

Amazing! Thank you!

[@user-yz6qu2jr9g]

Thank you, this was brief and clear, great help before my exam!

[@DrNic]

Glad it helped!