Sandy asked in 科學其他:科學 · 2 decades ago

幫我解釋有關統計的名詞!急!!

請幫我解釋什麼是Path analysis 和Multi-stage regression analysis

它們是什麼意思,有什麼用途,謝謝!

上課用的英文講義,看不太懂,請各位幫幫忙!謝謝!

急!

2 Answers

Rating
  • 2 decades ago
    Favorite Answer

    Path analysis (路徑分析)

    它是一種用來處理多個變項間關係的統計方法,仍屬於線性模型的範圍之內。1920年代,首先提出這樣的方法,當時他和Fisher在研究定量的遺傳學—它是遺傳學在統計方面的分支,企圖把孟德爾定律和生物進化論作結合,以便將孟德爾定律延伸到一些不斷變化的生物特性上;而這方面的研究不僅使得路徑分析得到發展,同時也帶動了迴歸、相關分析、ANOVA等統計方法的發展。

    路徑分析於1960年代開始被社會學家所採用,1970年代後更是普遍地應用在生態學研究方面;在生態學的研究上,它主要是被用來了解變數間直接或間接的關係及它們在比較上的效果。在這方面,路徑分析和其他線性模型不同的地方在於,它可測得居間的路徑,例如,假設我現在有三個變數X、Y、Z,它們的關係是:,則我們稱Y為居間變數,而路徑分析正可研究經由居間變數Y作用所得到的效果。在路徑模型裡,路徑的存在是根據研究者的假設 (hypothesis)(也許假設是來自先前的研究文獻),而非直接可由統計方法測得的。

    值得一提的是,路徑分析是結構方程模型的特例;結構方程模型裡可以同時研究可測變項和隱性變項,但是路徑分析只可用來研究可測的變項。

    Multi-stage regression analysis(多階段迴歸分析)

    由於假設有用性知覺是易用性知覺的函數,而有用性知覺及易用性知覺又同時是使用意願的解釋變數,因此可能有線性重合的問題。

    為解決此問題,計量經濟中多採用二階段迴歸法,簡稱2SLS,或三階段迴歸法,簡稱3SLS,甚或一般最小迴歸法,簡稱GLS。以上多階段迴歸分析的目的。

    多階段迴歸分析的目的,是要利用工具變數之估測值來代替有線性重合問題的變數。

    然而這種解決線性重合的方法,必須先經過模式的認定,因此多階段迴歸分析難以通過認定的要求,故仍有其限制。

    主要原因是路徑分析多忽略外生變數對中介變數的影響,否則模式會龐大無比,因此可提供作多階段迴歸之外生變數的數目不足。

    參考文獻

    1.online web of San Francisco State University

    http://online.sfsu.edu/~efc/classes/biol710/path/S...

    2.The University of Arizona

    http://nitro.biosci.arizona.edu/zbook/reviews/Mara...

    因徑分析的相關網站

    1.North Carolina State University

    http://www2.chass.ncsu.edu/garson/pa765/path.htm

    2.Arts and Sciences majors at the University of South Florida

    http://luna.cas.usf.edu/~mbrannic/files/regression...

    3.University of Exeter

    http://www.exeter.ac.uk/~SEGLea/multvar2/pathanal....

    4.Stanford University

    http://www.stanford.edu/class/ed257/exs/pathanal

    Source(s): 統計學
  • 2 decades ago

    Critical Path Analysis and PERT are powerful tools that help you to schedule and manage complex projects. They were developed in the 1950s to control large defense projects, and have been used routinely since then.

    As with Gantt Charts, Critical Path Analysis (CPA) helps you to plan all tasks that must be completed as part of a project. They act as the basis both for preparation of a schedule, and of resource planning. During management of a project, they allow you to monitor achievement of project goals. They help you to see where remedial action needs to be taken to get a project back on course.

    The benefit of using CPA over Gantt Charts is that Critical Path Analysis formally identifies tasks which must be completed on time for the whole project to be completed on time, and also identifies which tasks can be delayed for a while if resource needs to be reallocated to catch up on missed tasks. The disadvantage of CPA is that the relation of tasks to time is not as immediately obvious as with Gantt Charts. This can make them more difficult to understand for someone who is not familiar with the technique.

    A further benefit of Critical Path Analysis is that it helps you to identify the minimum length of time needed to complete a project. Where you need to run an accelerated project, it helps you to identify which project steps you should accelerate to complete the project within the available time. This helps you to minimize cost while still achieving your objective.

Still have questions? Get your answers by asking now.