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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
11

J型-發散統計量與數種適合度檢定統計量之比較 / Comparisons of J-divergence statistic with some goodness-of-fit test statistic

吳裕陽, Wu, Yuh Yang Unknown Date (has links)
Taneichi(1993)提出一個新的適合度檢定統計量J<sup>2</sup>,具有近似卡方分配的性質。然而在小樣本的情形下,計算機模擬結果顯示,它的估計顯著水準大於期望顯著水準。所以本論文的重點之一,就是對J<sup>2</sup>進行改進,根據不同的準則,來選取一個適當的常數a。我們建議對每一觀測次數加一常數0.32,作為我們修正後的統計量,這個統計量我們記為J<sub>1</sub><sup>2</sup>。   另一探討的重點是在比較皮爾生卡方統計量X<sup>2</sup>,概似比例統計量G<sup>2</sup>,Cressie & Read統計量 I(2/3),J<sup>2</sup>和J<sub>1</sub><sup>2</sup>之性質,我們想要了解在小樣本的情形之下,何者較接近於卡方分配,何者具有較強的檢定力。研究結果顯示,X<sup>2</sup>和I(2/3)較接近卡方分配,但J<sub>1</sub><sup>2</sup>又較G<sup>2</sup>及J<sup>2</sup>好;至於檢定力,我們發現沒有一個統計量在文中所探討的對立假設的情況下,同時都具有最大的檢定力。這些現象都可以用觀測次數對期望次數比值間的關係來解釋。 / Taneichi(1993) introduces a new goodness-of-fit statisticJ<sup>2</sup>, which has an asymptotic chi-squared distribution. However, the results of simulation indicate that the levels of significance are in general bigger than the nominal levels, which prompts us to device a version of J<sup>2</sup> statistic which would perform better under small sample size situations. We suggest adding 0.32 to each observed value and find that the adjustment indeed works rearonably well. This version of J^2 statistic is denoted as J(1)^2.   Although Pearson chi-square statistic X<sup>2</sup>, likelihood ratio statistic G<sup>2</sup>, Cresse-Read statistic I(2/3), J^2 and J(1) ^2 all have asymptotic chi-squared distributions, their small sample behaviors are not expected to be the same. Comparisons based on simulation studies are then made. The conclusions are as follows : (1) In terms of levels of significance, X<sup>2</sup> and I(2/3) behave more like a chi-squared distribution. Though J(1) ^2 does not perform as good as X<sup>2</sup> and I(2/3), it does outperform G<sup>2</sup> and J<sup>2</sup>. (2) In terms of powers, it does not seem that any of the test statistics has a clear advantage over the others.
12

基因晶片實驗其樣本數之研究 / Sample Size Determination in a Microarray Experiment

黃東溪, Huang, Dong-Si Unknown Date (has links)
微陣列晶片是發展及應用較為成熟的生物晶片技術。由於微陣&#63900;實驗程序複雜,故資&#63934;常包含多種&#63847;同&#63789;源的實驗誤差,為&#63930;適當的區分實驗中&#63789;自處&#63972;、晶片及基因的效應,我們提出混合效應變&#63842;&#63849;分析模型來調整系統誤差。針對各基因在不同實驗環境的差異性假設檢定問題,&#63965;用最小平方法推導出點估計以及對應的檢定統計&#63870;。本研究介紹多重檢定問題中的族型一誤差,並證明在此模型下,Sidak調整法為適當的多重檢定方法。在給定族型一誤差&#63841;的顯著水準,利用檢定力的公式,運算出在預設檢定&#63882;的最低水準下所需最小樣本(晶片)&#63849;。最後我們透過電腦模擬,以蒙地卡&#63759;法&#63789;估計檢定力與族型一誤差&#63841;,由模擬結果發現,採用此最小樣本數結果,其檢定&#63882;可達到預期的水準以上,並且其族型一誤差&#63841;皆適當地控制在顯著水準以內。
13

複迴歸係數排列檢定方法探討 / Methods for testing significance of partial regression coefficients in regression model

闕靖元, Chueh, Ching Yuan Unknown Date (has links)
在傳統的迴歸模型架構下,統計推論的進行需要假設誤差項之間相互獨立,且來自於常態分配。當理論模型假設條件無法達成的時候,排列檢定(permutation tests)這種無母數的統計方法通常會是可行的替代方法。 在以往的文獻中,應用於複迴歸模型(multiple regression)之係數排列檢定方法主要以樞紐統計量(pivotal quantity)作為檢定統計量,進而探討不同排列檢定方式的差異。本文除了採用t統計量這一個樞紐統計量作為檢定統計量的排列檢定方式外,亦納入以非樞紐統計量的迴歸係數估計量b22所建構而成的排列檢定方式,藉由蒙地卡羅模擬方法,比較以此兩類檢定方式之型一誤差(type I error)機率以及檢定力(power),並觀察其可行性以及適用時機。模擬結果顯示,在解釋變數間不相關且誤差分配較不偏斜的情形下,Freedman and Lane (1983)、Levin and Robbins (1983)、Kennedy (1995)之排列方法在樣本數大時適用b2統計量,且其檢定力較使用t2統計量高,但差異程度不大;若解釋變數間呈現高度相關,則不論誤差的偏斜狀態,Freedman and Lane (1983)、Kennedy (1995) 之排列方法於樣本數大時適用b2統計量,其檢定力結果也較使用t2統計量高,而且兩者的差異程度比起解釋變數間不相關時更加明顯。整體而言,使用t2統計量適用的場合較廣;相反的,使用b2的模擬結果則常需視樣本數大小以及解釋變數間相關性而定。 / In traditional linear models, error term are usually assumed to be independently, identically, normally distributed with mean zero and a constant variance. When the assumptions cannot meet, permutation tests can be an alternative method. Several permutation tests have been proposed to test the significance of a partial regression coefficient in a multiple regression model. t=b⁄(se(b)), an asymptotically pivotal quantity, is usually preferred and suggested as the test statistic. In this study, we take not only t statistics, but also the estimates of the partial regression coefficient as our test statistics. Their performance are compared in terms of the probability of committing a type I error and the power through the use of Monte Carlo simulation method. Situations where estimates of the partial regression coefficients may outperform t statistics are discussed.
14

排列檢定法應用於空間資料之比較 / Permutation test on spatial comparison

王信忠, Wang, Hsin-Chung Unknown Date (has links)
本論文主要是探討在二維度空間上二母體分佈是否一致。我們利用排列 (permutation)檢定方法來做比較, 並藉由費雪(Fisher)正確檢定方法的想法而提出重標記 (relabel)排列檢定方法或稱為費雪排列檢定法。 我們透過可交換性的特質證明它是正確 (exact) 的並且比 Syrjala (1996)所建議的排列檢定方法有更高的檢定力 (power)。 本論文另提出二個空間模型: spatial multinomial-relative-log-normal 模型 與 spatial Poisson-relative-log-normal 模型 來配適一般在漁業中常有的右斜長尾次數分佈並包含很多0 的空間資料。另外一般物種可能因天性或自然環境因素像食物、溫度等影響而有群聚行為發生, 這二個模型亦可描述出空間資料的群聚現象以做適當的推論。 / This thesis proposes the relabel (Fisher's) permutation test inspired by Fisher's exact test to compare between distributions of two (fishery) data sets locating on a two-dimensional lattice. We show that the permutation test given by Syrjala (1996} is not exact, but our relabel permutation test is exact and, additionally, more powerful. This thesis also studies two spatial models: the spatial multinomial-relative-log-normal model and the spatial Poisson-relative-log-normal model. Both models not only exhibit characteristics of skewness with a long right-hand tail and of high proportion of zero catches which usually appear in fishery data, but also have the ability to describe various types of aggregative behaviors.

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