Yahoo Answers is shutting down on May 4th, 2021 (Eastern Time) and beginning April 20th, 2021 (Eastern Time) the Yahoo Answers website will be in read-only mode. There will be no changes to other Yahoo properties or services, or your Yahoo account. You can find more information about the Yahoo Answers shutdown and how to download your data on this help page.

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

Rating
  • 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。

    例子:

    one-tailed test

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

    在這個情況下

    H0: μ = 0

    H1: μ > 0

    因我們是要研究是否有進步,所以若差了我們便不會計算在內。

    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~~~
Still have questions? Get your answers by asking now.