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Thread: I do not understand standard normal distribution

  1. #1

    I do not understand standard normal distribution




    Hi guys, I'm in dire help for standard normal random variable.
    I've looked at examples but they don't seem to help with the following questions.

    P ( z <= 1)

    P ( z <= 2)=

    P (Z < 2) =

    P ( Z = 0 ) =

    P( z <= 1.34) =

    Now I'm using r and am thinking its
    pnorm(z =<) but can't get it to compute

  2. #2
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    Re: I do not understand standard normal distribution

    Do you understand how to solve them using the z-table? This would be a good start. I'm unfamiliar with R. Maybe someone else can help you to that end. http://www.normaltable.com
    "I have discovered a truly remarkable proof of this theorem which this margin is too narrow to contain." Pierre de Fermat

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    Re: I do not understand standard normal distribution

    P ( z <= 1)

    P ( z <= 2)=

    Code: 
    ?pnorm
    
    # P(Z<= 1 ) = 0.8413447
    pnorm(1, mean = 0, sd = 1)
    # [1] 0.8413447
    
    # P(Z<= 2 ) =
    pnorm(2, mean = 0, sd = 1)
    # [1] 0.9772499
    So what is:

    P( z <= 1.34) =


    It says: what is the probability of ONE (so n=1) random standard (so mean=0 and standard deviation =1) normal variable being less or equal to 1.34?

    And please don't double post. It is annoying.

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    Re: I do not understand standard normal distribution


    Quote Originally Posted by GretaGarbo View Post
    P ( z <= 1)

    P ( z <= 2)=

    Code: 
    ?pnorm
    
    # P(Z<= 1 ) = 0.8413447
    pnorm(1, mean = 0, sd = 1)
    # [1] 0.8413447
    
    # P(Z<= 2 ) =
    pnorm(2, mean = 0, sd = 1)
    # [1] 0.9772499
    So what is:

    P( z <= 1.34) =


    It says: what is the probability of ONE (so n=1) random standard (so mean=0 and standard deviation =1) normal variable being less or equal to 1.34?

    And please don't double post. It is annoying.

    Hi there,
    so to calculate 1.34 is more or equal to z, we would just replace the formula with 1.34 so..
    pnorm(1.34,mean=0,sd=10)?

    To calculate Z < 2 we would just use pnorm(2...?

    Thank you very much for your response
    Yes I am sorry about double posting, not sure if this is the right subtopic to post on.

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