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Chris asked in 科學及數學數學 · 1 decade ago

Hypotheses Testing

做Hypotheses Testing時, 請問點樣去決定幾時用 one-tailed, 幾時用two-tailed呢

1 Answer

  • 1 decade ago
    Favorite Answer

    當你的 alternative hypotheses 是要證明不等於 null hypotheses,那麼就要用 two-tailed test 了。這情況下,不用考慮 alternative hypotheses 是大於或小於 null hypotheses。

    而 one-tailed test 是要特別指明 alternative hypotheses 是大於或是小於 null hypotheses 時用。


    one-tailed test

    An engineer wants to investigate whether the new adjustment improves the mechanism. For negative μ, it is worsened.


    H0: μ = 0

    H1: μ > 0


    two-tailed test

    Whether the time is altered.

    在這情況下,alternative hypotheses 是要證明time是有改變的。因此:

    H0: μ = 0

    H1: μ 不等於 0

    值得留意的是,兩者的test statistics不同的。

    例如two-tailed 的5% significant level,test statistics是1.96

    而one-tailed的5% significant level是1.645。

    Source(s): Myself~~~
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