Normal Distribution Practice Problems

Practice problem walk-through for the normal distribution.

[@miacarter501]

My Goodness, this video was a life saver! I don't know who you are, but I love you.

[@amenok2224]

Words cannot express how much this helped me. Simple and let me understand the concept far easier then what my book was showing it. Thanks!

[@MarlonBandoy]

Thank you so much. It's been years now that I stopped studying and haven't reviewed probability until such time that my friend asked for help with regards to this topic. I almost forgot the Z table until I found your video and get to remember the table. Your video is very helpful. Thanks for the steps.

[@conintava514]

Omg.. sir the moment you drew the 'z' variable in Standard Normal Deviation, everything about my probability class just made so much more sense. I'm so grateful I stumbled on your video. Thank youu!!

[@DylansAndHoes]

learnt more in this vid than a term at uni.... appreciate it man!

[@aaronarroyo2627]

Thank you so much @jason delaney! My professor has never once given how to do problems with a step by step check list like this. It makes it soooo much easier to understand and solve. I hate stats so much and this makes it easy!

[@HiYaCeeShabob]

this video has helped me understand this topic so much better. thank you!!

[@Avatar1454]

Thank you Dr. Delaney - appreciate the assistance.

[@aimanlombu]

Great Video! Prepped me for my exam tomorrow!

[@vanshikabawa5317]

Thanks darling! This was right what I needed an hour before my exam Polite applause

[@manusharma3212]

Love you bro, saved my exam..

[@poptropicawilliam]

helped me with one of my AP stats tests. Thank you sir

[@learner3300]

great video... Much appreciated.

[@ikecharles7071]

The first example is incorrect right? It was asking for more than 18,000 so you would have to use =1- I(.84322)

[@jodyang4022]

Sir, you have saved my life TYVM

[@amponsahebenezer990]

Sir Jason your video has helped me a lot but i want to know when to use a normal distribution when you are a given a problem instead of binomial, poisson or hypergeometric

[@martinwilkins7593]

HI Jason, Awesome! you kicked a goal on this one. Cheers

[@sumityelpale4911]

Understood completely🤩. Thankyou

[@Okeu_Masat]

You made my understanding to be much easier,😘😘😘 Thanks bro

[@historiasmagnatas]

Amazing video, great explanation, helping students arround the world :)

[@muhannadghazal1944]

thanks man, you are a life saver!

[@evidencekhosa7594]

Wow Thank you so much sir for this helpful video ill definitely recommend this to my friends

[@doslp]

For those of you who were asking why are the z score tables different: There are three types of normal distribution tables. He is using this one: faculty.ccp.edu/faculty/sgramlich/251/tablea-2.3.jpg www.mathsisfun.com/data/standard-normal-distribution-table.html

[@lucyvo860]

This video is very helpful!

[@Dpatwal7]

Really helpful. Would be awesome to see more practice questions getting solved by you on binomial distribution data..

[@sakshamsinghiinda7908]

Hey

[@4200ffrobin]

thanks man this really help me understand

[@erikagraace]

thank you so much for this! really really helpful!!

[@reddingtonraymond1129]

thanks man, this video increased your subscirber by one

[@ramonaghakhan7623]

You did awesome!

[@Ghzfr1]

there is a problem in the first Q? ........the value of P in green is 0.7995 rather than 0.2995??? Z score table value at 0.8432 is 0.7995 not 0.2995 check plzz

[@vusalmammadov2274]

HEY MAN GOD BLESS YOU THANK YOU VERY MUCH IT WAS REALLY USEFUL!!APPRECIATED!

[@AjithChanaka]

Thank you very much. Very usefull.

[@jamilagilliam2083]

THANK YOU!! This was very helpful!

[@KoachwithaK]

thank you very much.

[@econ_drd]

Thanks, Lucy! Let me know if you run into any problems or have any recommendations.

[@videosaboutnothing8147]

very helpful! thank you

[@fareshegazy9640]

Hi Jason, First thank you so much for wonderful easy way teaching,My question is , I understand 100% what you did in second stock example, but I don't understand the question meaning itself , the 40.578 will but the company in the top 10% , 10% of what ? is this top 10% related to understand what S&P500 is? ,I try to understand how can link statistics to the real world.Thanks again

[@albertjackson9236]

Those who use the normal distribution should always be aware that the independent values range from -infinity to +infinity. In reality, nothing has this range.

[@tklolmanha40]

Thank you.

[@aw2crhenaclairetpangilayan618]

sir Jason how to solve a normal distribution with mean=10 and SD=6 what is the area below 32? area above 27? area between 42 and 51? the x value that has 45% of the area below it? the x value that has 13% of the area above it? please answer for me sir

[@niki-mendozacatalan5903]

i dont understand is 0.8432 the area of z or the value of z? if yes, then why are you looking for the area between 0-Z?

[@mahendersam2159]

Whoa!! Thank you soo much😊

[@JakeTorres0206]

Hi this video is very informative. Can I use this for educational purpose?

[@econ_drd]

You can share the link, by all means.

[@JakeTorres0206]

Thank you..

[@morgannelson5529]

On P for the first problem, When you were using the Z table why did you go over to .4? I understand why you went to .8 because that's what Z began with, I just don't understand where the .4 came from.

[@econ_drd]

I went over to .04, because z was 0.84, so you go down to 0.8, over to 0.04 because 0.84 = 0.8 + 0.04.

[@YahyaNaell]

at 11:40 you said "0.4 will be our P" but when you look up for Z you go to 0.8 and in the first example at 7:40 you got ur Z from the 0.4 p's column !?!? can you explain this for me please ?! thanks

[@JacobSiegle]

Lets say you had the number 0.86. You go to the 0.8, and then to the 0.06. 0.8 + 0.06 = 0.86 our original number.

[@YahyaNaell]

Jacob Siegle thanks a lot,, i was a little bit nerves and i didn't get at the moment but i understood it after thinking a while !! .. and i passed in the exam :) thanks for reply

[@econ_drd]

yaya NHO Congrats on your exam!

[@gunelrahimli5868]

tomorrow I have a maths exam and my birthday, wish me a great marks

[@menashadesilva4147]

really helpful!! x

[@TheCJ86]

thank you

[@shakyabandara4910]

Thanks...helpful

[@WHY70122]

I'm so confused right now. How come your z-table different from mine? all the numbers are different by 0.5. For example, in your table, z (1) = 0.3413. However, my tables give z(1)= 0.8413

[@Shahbhai10]

Hi,@7:25, your z-table looks different than what I have. my z-table starts with 0.500 instead of 0.000 in the first box from the top left column. Why? How are the two z-tables different? I have attached my version of the z-table for you to compare. www.stat.ufl.edu/~athienit/Tables/Ztable.pdf

[@angiegongora6511]

I also have that version, it gives the WHOLE area to the left of Z, and it gives the area from 0 to the number he's looking for so ours helps us skip one step. all we have to do is subtract 1 to the area in the 1st problem and we get the area to the right of Z :)

[@niki-mendozacatalan5903]

and why is that our z-tables are different?

[@saurabhs4743]

Nice video

[@singhnsk]

Thank you a hundred times. Really wasn't getting it :)

[@andylo8078]

Is there any other method I can use to find P other than using that table?

[@econ_drd]

In Excel, you can use =NORM.S.DIST(), making sure that you are using the cumulative distribution function. For example, entering =NORM.S.DIST(0.84,1) will give you 0.7995 (0.5 for the left half + 0.2995 from this table). Check the help file for more.

[@racinerobinson]

shouldnt it have been 1 - 0.2995?

[@niallmcaffrey]

On the normal distribution table isn't 0.8/0.4 .7995?

[@ace19741114]

you are right its 0.7995

[@racinerobinson]

exactly.

[@xPanda617x]

Great video! Have an exam on this coming up and figuring it out from the book alone isn't that helpful :)

[@warotimi6182]

My question is why did you pick 1.2 for z value

[@econ_drd]

We picked 1.29 because it is the closest (on the table) to have 0.4000 between 0 and z that also has at least 0.4000 in there.

[@warotimi6182]

Thanks. But wish you replied earlier tho.

[@TreBlass]

How can we do it without using statistical table?

[@econ_drd]

Sanchit Agarwal you can use excel functions or a statistical calculator. in principle you can evaluate the cdf by hand.

[@TreBlass]

cdf, by using the pdf of Normal distribution with mean 0 and variance 1?

[@rohitkashyapu]

can you please elaborate why you've taken Z=1.29 ?

[@econ_drd]

Rohit Kashyap if you choose 1.28, that means there is 0.3997 between 0 and z or 0.5 - 0.3997 = 0.1003 in the upper tail. choosing 1.29 leaves 0.5 - 0.4015 = 0.0985 in the upper tail. The company wants their upper tail to be

[@rohitkashyapu]

thank you :) 😊

[@BrokenBlackSymphony]

Someone Posted this earlier Hi,@7:25, your z-table looks different than what I have. my z-table starts with 0.500 instead of 0.000 in the first box from the top left column. Why? How are the two z-tables different? I have attached my version of the z-table for you to compare. www.stat.ufl.edu/~athienit/Tables/Ztable.pdf PLEASE ANSWER! I need to know asap!!

[@farahkhan2072]

Hi can u please draw a multiple bell-shaped graph on excel i mean singles bells all merged in on graph

[@pankajjuneja7712]

Damn helpful

[@mobilbear]

it's 0.7995, not 0.2995

[@econ_drd]

you're using a different table, one that shows P(z

[@mobilbear]

thanks, got it

[@L30N4tER]

OMEGALUL

[@rocketrider1405]

it would be easier just to use a z-table of tail probabilities

[@econ_drd]

Yep. But that's not what my students had. :) Best is to know how to use all of them.

[@angelica3744]

Would be more helpful if you included the link to the .pdf you are using...

[@sebastianal96]

Te amo

[@isadoritz]

Why couldn’t you just do it on a piece of paper?!

[@chrishapalla3562]

normal distribution

[@ace19741114]

0,8432 on the table is 0,7995 not 0,2995

[@martinpardede5748]

there are 3 types of normal distribution table. You are using different table than what he is using..

[@xRogueVol2]

I didn't mean it lol. The internet is anonymous (enough) whooo!

[@apostolicfaithchurchofalln1408]

your video was great but try not to do so much smacking your lips

[@zekutoo]

Please don't smack your lips. It's like nails on a chalkboard. Other than that, nice video.

[@osamaalam7685]

stop making so many noises , its irritating , making one think that you are chewing gum

[@kamleshshah4176]

Gujarati drama

[@xPanda617x]

Great video! Have an exam on this coming up and figuring it out from the book alone isn't that helpful :)