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1	STATISTICAL METHODS IN MICROARRAY DATA ANALYSIS Huang, Liping 01 January 2009 (has links) This dissertation includes three topics. First topic: Regularized estimation in the AFT model with high dimensional covariates. Second topic: A novel application of quantile regression for identification of biomarkers exemplified by equine cartilage microarray data. Third topic: Normalization and analysis of cDNA microarray using linear contrasts. Applied Statistics
2	A study of the robustness of Cox's proportional hazards model used in testing for covariate effects Fei, Mingwei January 1900 (has links) Master of Arts / Department of Statistics / Paul Nelson / There are two important statistical models for multivariate survival analysis, proportional hazards(PH) models and accelerated failure time(AFT) model. PH analysis is most commonly used multivariate approach for analysing survival time data. For example, in clinical investigations where several (known) quantities or covariates, potentially affect patient prognosis, it is often desirable to investigate one factor effect adjust for the impact of others. This report offered a solution to choose appropriate model in testing covariate effects under different situations. In real life, we are very likely to just have limited sample size and censoring rates(people dropping off), which cause difficulty in statistical analysis. In this report, each dataset is randomly repeated 1000 times from three different distributions (Weibull, Lognormal and Loglogistc) with combination of sample sizes and censoring rates. Then both models are evaluated by hypothesis testing of covariate effect using the simulated data using the derived statistics, power, type I error rate and covergence rate for each situation. We would recommend PH method when sample size is small(n<20) and censoring rate is high(p>0.8). In this case, both PH and AFT analyses may not be suitable for hypothesis testing, but PH analysis is more robust and consistent than AFT analysis. And when sample size is 20 or above and censoring rate is 0.8 or below, AFT analysis will have slight higher convergence rate and power than PH, but not much improvement in Type I error rates when sample size is big(n>50) and censoring rate is low(p<0.3). Considering the privilege of not requiring knowledge of distribution for PH analysis, we concluded that PH analysis is robust in hypothesis testing for covariate effects using data generated from an AFT model. Survival analysis Proportional hazards(PH) model Accelerated failure time(AFT) model Covariate effect test Statistics (0463)
3	消費者對基因改造食品之願付溢價分析: 以餵食基因改造飼料鮭魚為例 / Evaluating Consumers' Willingness to Pay a Premium for Non-Genetically Modi¯ed Foods: A Case Study of GM-fed Salmon 林辰彥 Unknown Date (has links) 以往對於消費者對基因改造食品偏好及願付價格估計之研究，如 Moon (2001)、Chern et al. (2002)和Fu (2004)，都是將兩個研究目的分開個別處理，因此就統計的觀點來說，這樣的分析方式是比較缺乏效率的。本研究中提出一個整合式的分析方式，來分析台灣消費者對於基因改造食品的偏好以及願付溢價。本方法除了增進統計效率外，也同時納入願付價格分析中可能遇到因為受訪者對該財貨有強烈偏好，對於該財貨有再高價格都願意支付的傾向，因此預期本方法將可提供更高的準確度。為了研究台灣民眾對基因改造鮭魚的認知行為，中央研究院調查研究專題中心在2003 年進行了全台的電話訪問。而本研究發現台灣消費者願意多付目前平均市價之12%來購買非基因改造飼料餵食之鮭魚。此外，消費者本身對於基因改造科技的看法、對基因改造科技的了解、以及消費者的年齡將扮演影響消費偏好以及願付溢價的高低之重要因素。 / Previous researchers, such as Moon (2001), Chern et al. (2002), and Fu et al. (2004), attempted to analyze consumer preference toward genetically modi¯ed pro- duces and to estimate a willingness to pay for them. These two objectives, however, have been conducted separately and therefore are de¯cient in statistically e±ciency. An integrated technique is introduced to understand how consumers in Taiwan perceive genetically modi¯ed produce as well as how much they are willing to pay a premium simultaneously. Apart from improving statistical e±ciency, this newly proposed method also considers the possibility that consumers might be willing to any price if he/she strongly prefer this goods. Higher precision is expected under this scenario. To investigate how public perceive genetically modi¯ed salmon, Center for Sur- vey Research, Academia Sinica, conducted a telephone survey to Taiwanese con- sumers in 2003. Our study indicates that consumers are willing to pay a premium, about 12% of the average market price, for non-GM-fed salmon rather than GM-fed counter part. Moreover, the way consumers think of the risk regarding GM food, how much they know about GM food, and their age will all in°uence their consump- tion tendency and willingness to pay. 願付價格加速失敗模型 WTP AFT model
4	台灣地區基因檢測之意向及願付價格調查 / The Investigation of people's intention and their willingness to pay toward genetic testing in Taiwan 王荷惠, Wang, Ho Hui Unknown Date (has links) 本研究的目的主要是想要探討台灣地區的人民對於基因檢測的意向及願付價格。資料來自於中央研究院所主導的一項電話訪問，其中有關願付價格的部分是透過條件評估法的方式來取得。針對願付價格的分析，我們藉由潛在變數模型將受訪者對於基因檢測的知識、態度和自我認知等資訊萃取出來，並視為新的解釋變數來進行分析。此外，僅完成單界詢價過程的受訪者的資訊也和提供完整回答的受訪者一併納入分析。結果顯示一個人的性別、教育程度、宗教信仰傾向及對基因檢測的態度會顯著影響是否願意免費參加基因檢測的意願。而在詢價過程中，一開始受訪者被問及的金額和此人其基因檢測相關的知識程度影響了他（她）是否願意付錢參加基因檢測。至於在願意付合理價格的人們之中，他們的健康程度、收入和自家人的癌症病史則皆為影響價格高低的因素。 / This study is aimed to explore people’s intention and their willingness to pay (WTP) for genetic testing in Taiwan. A telephone survey using contingent valuation method (CVM) was conducted by the Academia Sinica to collect the data. There are three unique features that distinguish our data analysis approach from the others. First, the covariates related to a respondent’s knowledge, attitude and perception (KAP) on genetic testing are generated through the use of a latent trait model. Second, the information collected from a respondent who completed only the single-bounded part of the survey is also included in the analysis. Third, reasons given by a respondent is used to decide whether he/she is willing to pay a lower price or unwilling to pay any price. It is shown that one’s gender, education level, religious tendency and attitude all have significant impact on whether a respondent is willing to try a free genetic test. When it comes to pay for it, the initial bid asked and the degrees of knowledge affect his/her decision a lot. For those who are willing to pay a reasonable price for genetic testing, their WTP depend largely on their health conditions, incomes, and cancer histories. 願付價格基因檢測加速失敗模型 WTP Genetic testing AFT model
5	台灣地區公共電視使用之願付價格分析 / Assessing willingness to pay for maintaining the operation of Public Television Service in Taiwan. 黃慧甄, Huang, Huei Jhen Unknown Date (has links) 本研究主要目的是想要探討台灣地區民眾對於維持公共電視的營運與發展之願付價格。資料來自於中央研究院人文社會科學研究中心調查研究專題中心所進行的一項公共電視願付價格調查，其中關於願付價格的部分是透過條件評估法的方式取得，受訪者隨機分配至兩個題組之一，其中A題組為考慮公共電視帶給家人的好處，而B題組為考慮公共電視帶給全國民眾及社會的好處。建模時我們採用一或二要素混成模型，這是一個可以將不理性受訪者分離，僅針對理性受訪者的願付價格進行估計的一個模型。分析結果顯示考慮到公共電視帶給家人的好處時，年齡50歲以上的受訪者中存在著一群無論什麼價格都不願意支付或Ney-sayers的人，估計的比例大約為21.13%；而考慮到公共電視帶給全國民眾及社會的好處時，很少看文化教育節目的受訪者中也存在著一群無論什麼價格都不願意支付或Ney-sayers的人，估計比例大約為13.53%。針對願意支付合理價格的受訪者配適加速失敗模型時，我們不僅就位置參數引進解釋變數，同時也引進解釋變數至尺度參數。分析結果顯示願意支付合理價格的受訪者，在考慮公共電視帶給家人的好處時，每年願意支付價格之平均值為1477元；而考慮到公共電視帶給全國民眾及社會的好處時，每年願意支付價格之平均值為1663元。顯示受訪者在考慮到全國民眾及社會的好處，願意付出較高的價錢。 / This study aimed to explore people’s willingness to pay (WTP) for maintaining the operation of Public Television Service (PTS) in Taiwan. The survey using contingent valuation method was conducted by the Center for Survey Research, Academia Sinica. The survey sample was split into two groups, A and B. Each group was presented with the same scenario but different scope of benefits. Group A considered the benefits that PTS might bring to one’s family, while Group B considered the benefits that PTS might bring to the whole society. The model used in this study was a one/two-component hybrid model, a model that is able to separate those who are willing to pay a reasonable price from these who are not, and obtain their mean WTP estimate. Multinomial logistic part of the model, indicated that for Group A, among those who were 50 years of age or older, about 24.48% were not willing to pay any price or Ney-sayers. And for Group B, among those who seldom watched cultural or educational programs, about 12.91% were not willing to pay any price or Ney-sayers. Appling accelerated failure time model to those who were willing to pay for reasonable prices enabled us to evaluate the WTP. We not only introduced explanatory variables in the location parameter but also the scale parameter. The estimated mean WTP for Group A was found to be NT$1477 per year, while the mean WTP for Group B was NT$1663 per year. 願付價格二要素混合模型加速失敗模型 WTP two-component mixture model AFT model
6	條件評估法中處理「不知道」回應之研究 / Analysis of contingency valuation survey data with “Don’t Know” responses 王昱博, Wang, Yu Bo Unknown Date (has links) 本文主要著重在處理條件評估法下，「不知道」受訪者的回應。當「不知道」受訪者的產生機制並未符合完全隨機時，考量他們的真實意向就顯得極為重要。文中使用中央研究院生醫所在其研究計畫「竹東及朴子地區心臟血管疾病長期追蹤研究」（CardioVascular Disease risk FACtor Two-township Study，簡稱CVDFACTS）第五循環中的研究調查資料。　　由於以往的文獻對於「不知道」受訪者的處理，皆有不足之處。如Wang (1997)所提出的方法，就只能針對某種特定的「不知道」受訪者來做處理；而Caudill and Groothuis (2005)所提的方法，由於將「不知道」受訪者的差補與願付價格的估計分開，亦使其估計結果不具備一些好的性質。在本文中，我們提出一個能同時處理「不知道」受訪者且估計願付價格的方法。除了使得統計上較有效率外，也保有EM演算法的一個特性：願付價格模型中的估計參數為最大概似估計值。此外，在加入三要素混合模型(Tsai (2005))後，我們也可避免用到極端受訪者的訊息去差補那些「不知道」受訪者的意向。　　在分析願付價格的過程中，我們發現此筆資料的「不知道」受訪者，其產生的機制為隨機，而非為完全隨機，這意謂著不考量「不知道」受訪者的分析結果，必定會產生偏差。而在比較有考量「不知道」受訪者與沒有的情況後，其結果確實應證了我們的想法：只要「不知道」受訪者不是完全隨機產生的，那麼不考量他們必定會產生某種程度的偏差。 / This paper investigates how to deal with “Don’t Know” (DK) responses in contingent valuation surveys, which must be taken into consideration when they are not completely at random. The data we use is collected from the fifth cycle of the Cardiovascular Disease Risk Factor Two-township Study (CVDFACTS), which is a series of long-term surveys conducted by the Institute of Biomedical Sciences, Academia Sinica. Previous methods used in dealing with DK responses have not been satisfactory because they only focus on some types of DK respondents (Wang (1997)), or separate the imputation of DK responses from the WTP estimation (Caudill and Groothuis (2005)). However, in this paper, we introduce an integrated method to cope with the incomplete data caused by DK responses. Besides being more efficient, the single-step method guarantees maximum likelihood estimates of the WTP model to be obtained due to the good property that the EM algorithm possesses. Furthermore, by adding the concept of the three-component mixture model (Tsai (2005)), some extreme information are drawn out when imputing the DK inclinations. In this hypertension data, the mechanism of the DK responses is “Don’t know at random”, which means the analysis of DK-dropped results in a bias. By using our method, the difference between DK-dropped and DK-included is actually revealed, which proves our suspicion that a DK-dropped analysis is accompanied by a biased result when DK is not completely at random. EM演算法條件評估法三要素混合模型加速失敗模型 EM algorithm CV survey Three-component mixture model AFT model
7	Sur les familles des lois de fonction de hasard unimodale : applications en fiabilité et analyse de survie Saaidia, Noureddine 24 June 2013 (has links) En fiabilité et en analyse de survie, les distributions qui ont une fonction de hasard unimodale ne sont pas nombreuses, qu'on peut citer: Gaussienne inverse ,log-normale, log-logistique, de Birnbaum-Saunders, de Weibull exponentielle et de Weibullgénéralisée. Dans cette thèse, nous développons les tests modifiés du Chi-deux pour ces distributions tout en comparant la distribution Gaussienne inverse avec les autres. Ensuite nousconstruisons le modèle AFT basé sur la distribution Gaussienne inverse et les systèmes redondants basés sur les distributions de fonction de hasard unimodale. / In reliability and survival analysis, distributions that have a unimodalor $\cap-$shape hazard rate function are not too many, they include: the inverse Gaussian,log-normal, log-logistic, Birnbaum-Saunders, exponential Weibull and power generalized Weibulldistributions. In this thesis, we develop the modified Chi-squared tests for these distributions,and we give a comparative study between the inverse Gaussian distribution and the otherdistributions, then we realize simulations. We also construct the AFT model based on the inverseGaussian distribution and redundant systems based on distributions having a unimodal hazard ratefunction. Distribution Gaussienne inverse, Distribution log-normale, Distribution log-logistique, Distribution de Birnbaum-Saunders, Distribution de Weibull exponentielle, Distribution de Weibull généralisée, Test du Chi-deux, Test modifié du Chi-deux, Fiabilité, Analyse de survie, Modèle de Sedyakin, Modèle AFT, Systèmes redondants, Intervalle de confiance, Temps de panne, Maximum de vraisemblance, Estimation, Classes de Neyman-Pearson. Inverse Gaussian distribution, Log-normal distribution, Log-logistic distribution, Birnbaum-Saunders Distribution , Exponential Weibull distribution, Power generalized Weibull distribution, Chi-square test, Modified Chi-squared, Reliability, Survival analysis, Sedyakin's model, AFT model, Redundant system, Confidence interval, Failure time, Maximum likelihood , Estimation, Neyman-Pearson classes Maximum de vraisemblance,

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