Normal Distribution P(X more than x) : ExamSolutions

[superhardpack]

umm i have a question how did you get the 254.4 figure??

[ExamSolutions]

@superhardpack It was in the question at 1:40

[wasima222]

thanks a lot,,



[jac1398]

thank you ^^

[tsbsmj]

thanks for all ur help!

[ExamSolutions]

@tsbsmj That's ok

[vitovito123]

brother u forgot symmetry

[ExamSolutions]

@vitovito123 What do you mean?

[ExamSolutions]

@BWFTStudents Not really as you would still do the same calculation and get the same answer.

[AeroplaneWings]

Do I have to know this for Statistics 1 (MEI) ?

[vitovito123]

@AeroplaneWings yes

[EgyptianKid22]

How do you find the probablity between two points :S Eg find prob of that a bolt lies within +-1 mm from 60 mm. mean is 59.7 and 0.8

[supervernagirl]

wow that just cleared up a lots of things for me

theres me sitting here going: OMG THATS SO EASY!!!

thanks very much :)

[ExamSolutions]

@supervernagirl : Well done

[tearsofheaven786]

cont...

2) Instead of drawing the standardised representation of X into Z, why can't you just convert the X value into the Z score using the formula? Is it just a matter of convenience or is it part of the answer itself?

Thank You Doc. Once again, it's your videos that made me love Statistics. :)

[ExamSolutions]

I do it because I believe as a teacher that the whole picture of what is going on is important to see. However, you can just use the formula alone if you apreciate what is going on in your head. Examiners often like to see your train of thought though.

[Alfaomegabravo]

i felt you cheated when you used the table when the function used for it was defined

above :(

[tearsofheaven786]

Amazing video!! Your videos sereously serve as a life saver! :) I have 2 questions...

1)Could you please explain the significance of writing the 'variance' instead of 'Standard Deviation' when we write X~N(Mean, Variance) when at the end you use the square root of the Variance to solve the probability? Or is it just the way we write it?

[ExamSolutions]

It is just the way we write it.. You always divide by the standard deviation which is the square root of variance.

The variance is 16 so the standard deviation is 4.

[kpintheshed]

ty alot of help good for refreshing mind :)

[kami645464]

10q soo much

[taklusyndrome]

Awesome.... you should also have explained the percentage thingy... like

10 % of patients are late that 10 minutes.... so .1 will be the prob.

Anyways excellent vidd

[man4hire]

Very good

[Zedoloo]

Shouldn't you divide 254.4-250 by 16 because its the variance squared ?

[ExamSolutions]

No, you always divide by the standard deviation which is the square root of variance.

The variance is 16 so the standard deviation is 4.

[kellerwolves]

Cheers mate, my college teacher doesnt explain the graphs that you did very well and went straight into aswering the question threw the graphics calculator. She also hasnt mentioned the fi things in the formula book and only explained her way threw the graphics calculator

[bubbleking00]

excellent! my school only teaches students how to operate statistics using the graphic calculator without any understanding of what is going which is really bad for students who are good at pure math.

thank you (:

[MuslimahSouljette]

Thanks that helped a lot:)