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Confidence levels: How to find alpha if I know Z? Watch

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    If I already know the value of Z_\frac{\alpha}{2}, how do I go about finding \alpha?

    I'm after a formula, I know I can look up a Z table, but I'm making a computer program which needs to calculate alpha. Unless anyone knows any C# commands that will calculate it automatically!

    Help will be much appreciated.
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    (Original post by The Racist Dragon)
    If I already know the value of Z_\frac{\alpha}{2}, how do I go about finding \alpha?

    I'm after a formula, I know I can look up a Z table, but I'm making a computer program which needs to calculate alpha. Unless anyone knows any C# commands that will calculate it automatically!

    Help will be much appreciated.
    Another way of writing Z_\frac{\alpha}{2} is P(Z > x) + P(Z < -x) = \alpha, so you get P(|Z| > x) = \alpha, where x is your value for Z_\frac{\alpha}{2}.
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    (Original post by CTArsenal)
    Another way of writing Z_\frac{\alpha}{2} is P(Z > x) + P(Z < -x) = \alpha, so you get P(|Z| > x) = \alpha, where x is your value for Z_\frac{\alpha}{2}.
    Thanks for the help!

    How is P(Z > x) and P(Z < -x) calculated? I think my knowledge on the fundamentals of statistics is very rusty or non existent as I'm a little lost now.
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    (Original post by The Racist Dragon)
    Thanks for the help!

    How is P(Z > x) and P(Z < -x) calculated?
    What do you mean, as in how to work them out? They're equal to each other so essentially

    2P(Z > x) = \alpha.

    For instance, say your value of Z_\frac{\alpha}{2} was 1.32, \alpha = 2P(Z > 1.32).

    This gives us \alpha = 2(1 - 0.9066) \Rightarrow \alpha = 0.1868.
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    (Original post by CTArsenal)
    What do you mean, as in how to work them out? They're equal to each other so essentially

    2P(Z > x) = \alpha.

    For instance, say your value of Z_\frac{\alpha}{2} was 1.32, \alpha = 2P(Z > 1.32).

    This gives us \alpha = 2(1 - 0.9066) \Rightarrow \alpha = 0.1868.
    Oh that example cleared things right up, thank you!
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    You can boost your confidence levels and truly become alpha by going to the gym, shooting up the test and shooting ropes in all kinds of men and women. That, is the true meaning of an alpha. good lukc brah stay shredded n make u some gains!!
 
 
 
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