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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.
1

群集樣本具巢狀誤差結構之迴歸分析 / Regression analysis for cluster samples with nested-error structure

賴昭如 Unknown Date (has links)
分析具有巢狀誤差結構的迴歸模式時,惹忽略隨機誤差項之間的相關性,而採用最小平方(OLS)估計量所導出的標準 F 統計量(以 F<sup>S</sup>表之)進行檢定,會導致過大的型 I 錯誤機率;若將隨機誤差項之間的相關性納入考量,而採用廣義最小平方(GLS)估計量所導出的 F 統計量 (以 F<sup>GLS</sup>表之),則計算上會較為繁雜。因此我們藉由轉換方式,將模式轉換成隨機誤差項之間彼此獨立的新模式後,再以 F<sup>S</sup> 進行檢定,其結果與直接以 F<sup>GLS</sup> 檢定相同,且可使計算較為方便。由於模式轉換所需的轉換矩陣為母體變異數的函數,因此當母體變異數未知時,我們以 Henderson 的常數配適 (fitting-of-constants)方法來估計之。藉由模擬結果得知,若各段的觀察個數相等,則不論巢狀誤差結構為二段式(two-stage)或三段式(three-stage),廣義最小平方估計量(GLS)均較最小平方估計量(OLS)表現穩定,且 F<sup>GLS</sup> 在檢定力及實際顯著水準方面的表現也都比 F<sup>S</sup> 好。 / When analyzing the regression model with nested-error structure, if the correlations between errors are ignored, and conduting the model adequacy test by the standard F statistic (F<sup>S</sup>) led from the ordinary leastsquares estimator (OLSE) , then the type I error rate will be inflated. However, if the corrlated structure is considered and the model is tested by F<sup>GLS</sup> led from the general least-squares estimator (GLSE) , the calculation will be more complicate. The model can be transformed to a new model with independent random errors and then, tested by F<sup>S</sup> . The result is the same as the one by F<sup>GLS</sup> , also it is more convenient for calculation. Since the transformation matrix is a function of variance components, we estimate variance components by Henderson's fitting-of-constants when they are unknown. Through simulation, it is concluded that if the observations in each stage of nested-error structure are the same, the GLSE is more stable than the OLSE in both two-stage and tree-stage structures. Also, the power and the sizes of F<sup>GLS</sup> will perform better than those of F<sup>S</sup> .
2

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.
3

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。

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