Normal Distribution & Z-scores

This video shows how to calculate "inside areas" and "areas in the extreme" in a normal distribution using Z-scores. This video can also be found on my website statstutor.books.officelive.com

[@TheBigFella]

thanks for taking the time to put this together - guys like you make the world a better place by freely making education available to the masses for free - you rule!

[@LFSPharaoh]

overpriced academia be like "THEY TOOK OUR JOBS!"

[@masoomaaslam2613]

Oisin Hughes stay blessed

[@user-fg3mi3vk1s]

Oisin Hughes Thank you very much. My form teacher are perfectly in knowledge however he doesn't know how to teach ,under his teaching the students cannot really understanding what is real normal distribution and only on remember the fix formula. If you remember the formula you get the score If you don't,you can't pass the exam. That was why most of the our class had failed this subject years ago.NOT on understand but on memory

[@user-fg3mi3vk1s]

Oisin Hughes this had shows the difference way on the teaching. Instead of memory teaching.make students understand are more helpful.Thanks you again

[@PhysicsThroughComputation]

kzbin.info/www/bejne/ZmOcnZSNeLqCoJY

[@MissWooHoo11]

I love how you did it multiple times. Its 1 million times better than other vids when they just show you once. This really gets it through your head.

[@supiriorthinker9580]

your head! It like most degrees are apparent to me before doing them!

[@Freacoolize]

whos here for tomorrow's exam

[@forcabarca4607]

lol me

[@ehm2538]

me grade 9 student huhuhu

[@sevenohseven3830]

ME ME

[@heneraltonton4164]

hahahahah me

[@ariloveshouse]

SAMEEEEE

[@BobotheDoritoBandit]

this is honestly what I look for in a online math video , no rambling... you nailed it.

[@MoyoTaiwo]

After hours of laboring, and countless youtube videos, I finally got one that broke it down in bits and pieces. For one who is coming from a not too sound mathematical background, this video has been a life saver in understanding normal distributions. I'll now go ahead and tackle probability with this new found knowledge. Muchos gracias!!!

[@xGoldenArrow]

Way easier to understand than my stats prof

[@chrstnSalgado]

+GoldenArrow AGREED

[@bushybrovvs]

For those of you who have different charts, you're suppose to subtract the z-scores from one another instead of adding them like he does. For example, with the second problem: If you look at your chart and get .02275 for -2.00, and .97725 for 2.00; SUBTRACT them. When you subtract .02278 - .97725, you get 95.45. It isn't 95.44 but its close enough... I did the same thing with the first problem. I got z-scores .15866 for -1.00 and .84134 for 1.00. When I properly subtracted them, I got 68.26.

[@kadyr8935]

Thank you so VERY much for this comment! I was going crazy trying to figure out why I couldn't get the same answer!!

[@victorfernandes7955]

Straight forward, simple, no unneeded explanations. Just what I was looking for. Thank You

[@Jordi_Plays]

This is a miracle. I didn't get this until I watched your video and my final is tomorrow morning. XD thanks for sharing!

[@soliderarmatang5664]

how did your final go?

[@Naamy19X9]

+Moonfall Hey as someone who has written a final on this, can you please explain the last example? He spoke about a standard rule and 3 standard deviations...what is that all about?

[@Gealamusic]

I'm in the exact same position, 6 years later XD

[@zeroc977]

My teacher was explaining this to the class for around 2 classes and most of us didnt get it. This video is the best!

[@Sumweight]

You're a life saver! Been studying for final and was having issues until watching your video. THANK YOU.

[@zuzol735]

I was in a 3 hour lecture at uni not being able to understand it at all and you explained it in 10 minutes.... impressive ! Thank you so much.

[@kevin71794]

so much clearer and easier to understand than coming from an old PhD professor....and the book. needless to say what i spent hours trying to comprehend I easily learned by watching this video twice. No bs. straight to the point. How teaching should be.

[@nc7182]

I have my first math exam in two years tmrw and doing the textbook problems had me so stumped. I'm solving these with you and pausing so I can test myself and beat you to the next step. I'm nailing all these and feeling way more confident about not only solving the problems but also about the logic behind it all. Thanks so much for this great video :)

[@wangxingyu575]

clear as hell, i was doing CFA level 1 test and struggling with normal distribution! your lecture is amazing.. it helps a lot, thx buddy

[@brendaliz1989]

This was amazing. I finally get z scores. I love the fact that you went step by step and gave several examples. Nicely done

[@sharynmain2432]

Thank you so much for keeping this video concise, simply and straightforward. The hours I have invested in this week only, by being at Uni have tested my sanity in regards to normal distribution. It is now getting synthesise in my being slowly but surely. My lecturer, oddly enough commented on how many tabs I had on my laptop when helping me with something , little does she know I have spent about an hour and a half just searching through videos on this subject….I wish I had found this earlier . It just shows you the algorithm is truly watching your moves…. Just think about that for a moment. Thanks again for your generosity.

[@KH-iq7qo]

Thank you! This makes so much sense. My book made is seem like greek! Please post all of your teachings! Teachers like you make the world a better place.

[@ddigwell]

LOVE how simple and to the point, you make this!

[@pistalo1]

thanks so much. learn more in this ten minutes than class for the last two weeks

[@mochalatte2965]

THANK YOU SO MUCH. I have a college class certification due in 4 days and this really helped me understand bell curves and standard deviation with percentages. You rock!

[@MrSafa61]

Seven years later, a random Turk from the Netherlands comes by, learns what the system didn't want to provide, or assumed we already knew, and leaves again. Thank you for putting this here. Out of all the videos out there, only yours helped me out.

[@TheGeorge3011]

How come the Z table I was given in class is different ? at 1.00 on my Z tableI have .8413

[@ronanogales7247]

i got that allso that value but i did i the sci cal...not actually on z table

[@AJRadaza]

It's because the area for the z in your table starts from -3.5 to 3.5. Not from 0 to 3.5. For your case, just subtract .5000 of the given cumulative area. Sorry for posting this 4 years after your comment.

[@brendag331.]

same

[@aceroargentino1049]

AJ Radaza lmaoooo 🤣🤣🤣🤣🤣

[@rahmahdalhat8484]

@@AJRadaza no thanks for posting this.I am having problems and this was helpful...but mine starts from _3.0

[@livinlavi-donnisha7359]

omg hes saved my life! i was freaking out about my exam coming up

[@Shabz1031]

you made this so easy to understand in 10 minutes when my teacher spent 1 hour trying to figure out how she did it the first time... Thank you so much

[@papag3324]

Just wanted to say thank you! I'm in beginners Stats class and could not figure a certain problem out...random person scoring above 65%. Your instruction on IQ of greater than 130% helped me out! Thanks again!!

[@AllaahuAkbar60]

This professor is so awesome that Majority of people can understand Z score calculations within 10 minutes :)

[@TheMcginty222]

My poor head don't understand the concept yet , but after strolling dozens of videos , your video game high hopes , thank you , i like the steps you go through, my professor is like a hurricane !!

[@anonymous12726]

you explain it very concisely and it's straight to the point. It's helped me tremendously. Thank you. I think, learning the symbols that correspond to this language are the hardest part when understanding this concept. Also, it's essential to understand the formula when solving these problems. My Professor didn't explain it so I understood it or didn't take the time. Your online video shows all this in an easy to understand format. Keep up the good work in helping people work through challenging concepts in an easy manner.

[@kurbennnm3404]

Bless your soul Man, you just saved me

[@miranda3093]

finals in about 2 hours and you made more sense in 10 mins than my lecturer in 3 months - thank youuu

[@angelburgos2921]

i finally understand how to apply the information from class. thank you so much

[@ivanburgos4529]

te iban a raspar con esa materia.

[@angelburgos2921]

Ivan Burgos iban... jejeje ahora no

[@ivanburgos4529]

Dios te bendiga muñeco

[@jaimeetreloar5667]

thank you so much. this video has helped me heaps. i didnt understand this at all until i watched this. great information

[@NoraIsmailwins]

I like this explanation. It's simplified and dummy-friendly.

[@GunjanSubedi]

supirior thinker, 1. plz correct your spelling first, .....2. when u feel urself superior and start to boast, u actually lose ur ability to learn more...there are still millions ideas to learn....and 3. ur bragging looks like u really learnt about "black-hole" at 15 becoz by then u started reaching adolescence...4. I learnt by heart an epic book >2000 pages "mahabharata" by 10, calculus by 8, steriochemistry by 12, Molecular medicine by 15, and completed my phd in 23.... !!! and still i am learning basic statistics becoz, i missed learning it since long !!! so fuck u !!

[@lulublu88]

Finally! an explanation that makes sense!. thank you so much! i've spent hours trying to figure this out and you did it in 10 minutes.

[@moviemaker667]

This topic can be really difficult the first time learning them, but once it clicks (Which can take a while), it's not so bad. You seem to help it click a lot more quickly than it otherwise would!

[@MrJassu2]

This has to be 1 of the best video out there on Zscore...thanks

[@danpluso]

@rockentui You may be getting confused by the two different chart versions like I myself was a few days ago. It seems like the most common chart used in classes is the "Area from the left" chart while this video is using the "Area from the mean" chart. Add a .5 to the last value on his chart (Z=3.9) and you will get the .9990 that is on the "Area to the left" chart.

[@leam6371]

Thank you so much! My final exam is in 30 mins and you’ve made this really clear for me!

[@dan576-b9f]

Thankyou for the video, it really helped to how this precisely and clearly

[@Jenigami]

Thank you for explaining this so clearly!

[@syl860]

thank you bro! i need this tomorrow for my exams

[@annaschow9188]

I know this video was uploaded literally 8 years ago, but now it all makes sense and I’m going to pass my standard

[@souleaterROX88]

I now feel that I may actually pass this unit. Thank you so much for taking the time to make this video.

[@heya9302]

OMG THIS IS GOOD THANK YOU FOR SAVING ME OF MY SCREWED UP LIFE. MY EXAM IS IN LESS THAN 12 HOURS

[@NINABURROUGHS123]

Thank you so much for the most simplest breakdown ever!!!!!! I wish you taught at a college near by my residence. Thank you

[@fgestosani]

Thanks for not talking too much and making it sound so easy/simple!!!

[@so0osa]

I can't believe it's that simple!! Thank you so much for making my life easier

[@zoehowell5589]

This helped refreshed my memory! Have a final tomorrow

[@habiburrehman327]

you are genius...at least for for me .. you are between those very tiny percentage of people who can explain this in such a easy way ... God Bless

[@uruminati5382]

This video is absolute genius! Thanks so much, you made it just so easy to understand

[@BismillahArif]

The most easy and useful in all KZbin videos of normal distribution thank for easy explanation ready for exams now

[@jazminegipson6934]

this video was so helpful! thanks for doing multiple examples with different problems!!

[@smvsiyer]

Excellent. This example can be replicated in any set of scores - including employee performance , Ranking of companies in revenue performance, etc.

[@dr.ashuroulet7462]

Good explanation. Please answer my question that is it necessary to convert raw data in z scores to check your normality?

[@yasharanathaniel9291]

Finally understood how this works!!! THANK YOU SO MUCH!

[@gazellerose2584]

BEST EXPLANATION OF THIS TOPIC! THANK YOU SO MUCH

[@annegelenb.7336]

life saver thank you for this video because my teacher in statistics get mad on us then he told that he is going to have a quiz but he didnt discuss this very well

[@Drcalvinklein]

you explained what my professor (who has a phd and whos been published dozens of times) could not. Sir, I tip my hat to you, and id like to buy you a beer (if your ever in the area). Many thanks.

[@xAlternateUniverse]

thanks for this!!! :D I finally understand it- although I must say, I don't really pay attention in class O.o I think I'm ready to take on more difficult examples now :D

[@xmediabox]

Americans are the most Generous People on the planet top education for free. I never meet people like you here in Germany I love America. clear and very helpful

[@NoraIsmailwins]

Yes, our education system is awesome because we give financial aid to people that can't afford school :) Most of us are generous with knowledge too.

[@BbyGLK]

supirior thinker how are u so rude to ppl when youtube name is spelled wrong? humble yourself and stop with the negativity

[@ColbyTheNisest]

have a test tomorrow and this video just saved my life

[@Stanger1252]

Thank you sir! I was trying to learn this from the text for the last hour.. you made it so much easier!!

[@NightsareStarry]

Thank you so much :) I realized I should thank each video that teach well. You are one of them, Mister! Keep going :)

[@meteoriter1647]

The percentage of dislikes to likes for this video at this moment is 234 out of 5.7K or 4.1% lying outside 2 standard deviations or 100 - 2 x 47.72 = 4.56% ! Meaning the dislikers are insignificant critics to this well-made video. Thanks pspollard1 !

[@monicag.6462]

Is it too much to ask for additional examples? This was BEYOND GREAT and something I haven't seen that goes straight to the point!

[@tiffanysarafian9739]

thank you, this helped so much. i can not explain how glad i am i found this video

[@etch.asketch2420]

Great tutorial. This really helped me to understand normal distribution and z graphs.

[@Slickster52]

This is good stuff, well explained and very helpful. Thank you!

[@leejohnson197733]

if i have a median of 21.8 and a varient of 1 how do i create a graph to show the the area between 19-24 ?

[@Jasmine13096]

This video has really helped me. Thank you for putting it up.

[@johannespkassing]

Thank you for this video. How do you start with a Standard Deviation of 15 though? Is that just as it is. How do you get there?

[@coolerthanyou1235]

Omg thank you finally I’ve been looking for a vid like this on bell curved

[@wargarblet3498]

My instructor is incredibly bad. He rambles, starts and stops at odd points, and generally makes no sense. He does a poor job of relating the information he's spewing out to what it actually represents, and to top it all off, he wrote his own text for the class which makes just as much sense. I had no idea how to do my homework. Class has been in session for almost a month. By 7:47 in this video, you've already managed to teach me more than he has thus far this semester. I can't thank you enough for posting this.

[@madzo.e.mwadzoya]

my life was missing this information. Good work!!!

[@jadelee6555]

Thank you so much for the examples! Best video of normal distribution I've found on youtube :)

[@lwc888]

Thank you! You made it simple to understand. The CFA study guide made used 900 variables and made it so impossible to understand. Could have explained what the z score and z table mean in one sentence.

[@sergioalvarez8710]

This guy is so good and I'm learning this stuff in my sophomore year

[@sergioalvarez8710]

Of high school

[@Philaundre]

Best video for Normal Distribution & Z-scores.. -Thank you for this!!!

[@kelly_browning]

Really great explanation. I wish I would've seen this video before I crashed and burned on my test :/ But thanks for putting this up. Super helpful!

[@jamessaldua730]

When my teacher introduced this topic I got overwhelmed by the name, goos thing she linked your video to the classroom.

[@geetc.4996]

That was explained perfectly! what tool did you use to create this? I'm currently using powerpoints

[@tubulartels]

Excellent work. The only confusion might arise from calling the table data that you look up “distances” when they are actually the AREA under the curve. You do say area in the example where you have to subtract it from 0.5 to determine the “greater than” AREA. For those of you with the double data values, you4 chart is giving the area between the -x and +x value of the z score.. so it’s double the area.

[@smvsiyer]

You are right. It is formally called "area under normal curve"

[@nicolauandrade7075]

Thanks, I have been looking help on this exact examples you have uploaded. You made very easy to understand probability distribution.

[@shellymorgan1159]

Thank you so so much!!!! This is the best video I have seen so far!

[@niveshsimon699]

Love this you explain nice and simply that it looks so easy to understand now...Thanks mate

[@sibekezelosibanda4216]

wow...this vid makes everything so much easier and understandable,thank you!

[@199alexman]

question how would i find value of c if i have mean= 3.6 and Stndrd div of 0.1 of p(-c

[@jamjoe01]

Is there a good place to find a common table that also explains the type of table being supplied?

[@Nunuvang]

Thank you sooooo much! This makes a lot more sense than it did in class.

[@jennyleepunan798]

such a wonderful video! thanks a lot

[@cassandrarowe9098]

This has just saved me from failing stats due to having a terrible professor! Thank you so much for the video!

[@charlesanthonylatag6382]

Thanks for this video. I was enlightened with the topic. Such a great help!

[@emichh4]

wow you helped me so much. so explain everything so clear and went step by step. thanks!

[@Bellyfresco]

Should you add or subtract when you are given a problem of "between"? Some teachers stated different kinds of methods.

[@kalgaalissa753]

when do you know when to add or subtract the z-scores??

[@bbestblows1]

Dude, thanks for the vid! I've watched about 6 videos prior to this one and they were all junk. Just subbed!

[@salimalsenani8169]

i have an exam after 3 hours about this .. i am very thankful for u

[@patrickhaller5742]

Wouldn't the z-score actually denote the area under the curve between the mean and x1/x2 instead of the distance? Or did I mix up concepts here?

[@samkab677]

Can z score and t score be used in non parametric test ? If no what is the equivalent formula?