• Journal of the Korean Data and Information Science Society
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• 제17권4호
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• pp.1067-1076
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• 2006

Although the proportional hazards model is the most common approach used for studying the relationship of event times and covariates, alternative models are needed for occasions when it does not fit data. In the two-sample case, proportional odds models are useful for fitting data whose hazard rates converge asymptotically. In this thesis, we propose a new estimator of the relative odds ratio of the proportional odds model when two independent random samples are observed under uncensorship. We prove the asymptotic normality and consistency of the estimator by using martingale-representation. The efficiency of the proposed is assessed through a simulation study.

• 치위생과학회지
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• 제8권3호
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• pp.169-173
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• 2008

본 연구는 2007년 3월10일부터 2007년 6월3일까지 충남 당진에 위치한 S대학 치위생과 3학년들의 치면세마 실습환자 248명을 대상으로 치간칫솔 사용에 따른 치면세균막 제거효과를 비례오즈모형(proportional odds models)을 사용하여 분석한 결과 다음과 같은 결론을 얻었다. 1. 비례오즈모형의 적합도는 자유도가 3인 1.2552이고 p값이 .7398로 비례오즈모형이 적절함을 의미하고 치면세균막 제거효과와 치간칫솔 사용의 독립성문제는 $H_0:{\beta}=0$에 대한 검정으로 검정통계량은 자유도가 1인 15.5496이고 p 값은 <.0001 이다. 이는 치면세균막 제거 효과와 치간칫솔의 사용은 매우 연관성이 높음을 의미한다. 2. 모형의$\beta$에 대한 ML추정치는 $\hat{\beta}=1.2493$(ASE = 0.3207)임을 알 수 있고 반응이 매우 불량이다 보다는 매우 양호하다 에 속할(이를 라 표현할 수 있다) 경향은 치간칫솔을 사용하지 않는다. 라는 반응에 비해 치간칫솔을 사 용한다. 라는 경향이 추정오즈비 exp(1.2493) = 3.49배 높다. 3. 비례오즈모형의 추정반응은 치간칫솔을 사용한다. 라는 반응이 매우양호와 양호한 치면세균막 제거효과에 속할 추정(누적)확률은 0.38(0.50)이다.

• 운동영양학회지
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• 제25권1호
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• pp.30-34
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• 2021

[Purpose] Many studies have observed a high prevalence of erectile dysfunction among individuals performing physical activity in less leisure-time. However, this relationship in patients with type 2 diabetic patients is not well studied. In exposure outcome studies with ordinal outcome variables, investigators often try to make the outcome variable dichotomous and lose information by collapsing categories. Several statistical models have been developed to make full use of all information in ordinal response data, but they have not been widely used in public health research. In this paper, we discuss the application of two statistical models to determine the association of physical inactivity with erectile dysfunction among patients with type 2 diabetes. [Methods] A total of 204 married men aged 20-60 years with a diagnosis of type 2 diabetes at the outpatient unit of the Department of Endocrinology at PSG hospitals during the months of May and June 2019 were studied. We examined the association between physical inactivity and erectile dysfunction using proportional odds ordinal logistic regression models and continuation ratio models. [Results] The proportional odds model revealed that patients with diabetes who perform leisure time physical activity for over 40 minutes per day have reduced odds of erectile dysfunction (odds ratio=0.38) across the severity categories of erectile dysfunction after adjusting for age and duration of diabetes. [Conclusion] The present study suggests that physical inactivity has a negative impact on erectile function. We observed that the simple logistic regression model had only 75% efficiency compared to the proportional odds model used here; hence, more valid estimates were obtained here.

• 응용통계연구
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• 제29권7호
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• pp.1231-1246
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• 2016

경쟁위험에 대한 연구 중 주로 쓰이는 방법은 Cause-specific 위험 모형과 subdistribution을 이용한 비례 위험 모형 방법이다. 그 이후에도 많은 모형이 제시되었지만, 추정 방법 면에서 설명력이 부족하거나 알고리즘으로 구현하기 어려운 단점을 가지고 있어서 잘 활용되고 있지 않다. 이 논문에서는 Cause-specific 위험 모형, subdistribution을 이용한 비례 위험 모형과 비교적 최근에 제시된 이항 회귀 모형(direct binomial model), 절대 위험 회귀 모형(absolute risk regression model), Eriksson 등 (2015)의 비례 오즈 모형(proportional odds model)을 소개하고 추정 방법을 간단히 설명하고자 한다. 각 모형에 대하여 SAS와 R을 이용한 활용 방법을 제시하고, 두 가지 경쟁위험이 존재하는 데이터를 R을 이용하여 분석하였다.

• Communications for Statistical Applications and Methods
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• 제24권6호
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• pp.605-625
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• 2017

This paper presents proportional odds cure models to allow spatial correlations by including spatial frailty in the interval censored data setting. Parametric cure rate models with independent and dependent spatial frailties are proposed and compared. Our approach enables different underlying activation mechanisms that lead to the event of interest; in addition, the number of competing causes which may be responsible for the occurrence of the event of interest follows a Geometric distribution. Markov chain Monte Carlo method is used in a Bayesian framework for inferential purposes. For model comparison some Bayesian criteria were used. An influence diagnostic analysis was conducted to detect possible influential or extreme observations that may cause distortions on the results of the analysis. Finally, the proposed models are applied for the analysis of a real data set on smoking cessation. The results of the application show that the parametric cure model with frailties under the first activation scheme has better findings.

• Journal of the Korean Data and Information Science Society
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• 제24권6호
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• pp.1465-1475
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• 2013

The chi-square type test statistic is the most commonly used test in terms of measuring testing goodness-of-fit for multinomial logistic regression model, which has its grouped data (binomial data) and ungrouped (binary) data classified by a covariate pattern. Chi-square type statistic is not a satisfactory gauge, however, because the ungrouped Pearson chi-square statistic does not adhere well to the chi-square statistic and the ungrouped Pearson chi-square statistic is also not a satisfactory form of measurement in itself. Currently, goodness-of-fit in the ordinal setting is often assessed using the Pearson chi-square statistic and deviance tests. These tests involve creating a contingency table in which rows consist of all possible cross-classifications of the model covariates, and columns consist of the levels of the ordinal response. I examined goodness-of-fit tests for a proportional odds logistic regression model-the most commonly used regression model for an ordinal response variable. Using a simulation study, I investigated the distribution and power properties of this test and compared these with those of three other goodness-of-fit tests. The new test had lower power than the existing tests; however, it was able to detect a greater number of the different types of lack of fit considered in this study. I illustrated the ability of the tests to detect lack of fit using a study of aftercare decisions for psychiatrically hospitalized adolescents.

• 한국조리학회지
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• 제12권3호
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• pp.49-60
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• 2006

The purpose of this study was to measure the factors influencing on the perception of helpfulness of marking the country of origin in predicting the quality and safety of pork. A total of 239 questionnaires were completed. A multinomial logit model is specified in order to estimate which factors influence the probability that a consumer perceives the country of origin as helpful in assessing food quality and food safety. The estimations were carried out using the logistic procedure of SAS. The results are as follows. The proportional odds assumptions of models were not violated at p<0.05. The effects of age, income, children, occupation and respondents informed on the importance of the country of origin in pork quality model were statistically significant. The effects of age, children, occupation and trust on the importance of the country of origin in pork safety model were statistically significant. The results from this study could be useful in developing marketing and health promotion strategies as well as government trade policies.

• Communications for Statistical Applications and Methods
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• 제16권4호
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• pp.697-705
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• 2009

The Pearson chi-squared statistic or the deviance statistic is widely used in assessing the goodness-of-fit of the generalized linear models. But these statistics are not proper in the situation of continuous explanatory variables which results in the sparseness of cell frequencies. We propose a goodness-of-fit test statistic for the cumulative logit models with ordinal responses. We consider the grouping of a dataset based on the ordinal scores obtained by fitting the assumed model. We propose the Pearson chi-squared type test statistic, which is obtained from the cross-classified table formed by the subgroups of ordinal scores and the response categories. Because the limiting distribution of the chi-squared type statistic is intractable we suggest the parametric bootstrap testing procedure to approximate the distribution of the proposed test statistic.

• Journal of the Korean Data and Information Science Society
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• 제15권2호
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• pp.367-378
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• 2004

Recently logistic regression is popular in a variety of fields so that a number of statistical packages are developed for analyzing the logistic regression. This paper briefly considers the several types of logistic regression models used depending on different types of data. In addition, when four statistical packages (MINTAB, SAS, SPSS and STATA) are used to apply logistic regression models to the real fields respectively, their scope and characteristics are investigated.

• 한국생활과학회지
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• 제15권5호
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• pp.859-866
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• 2006

The aim of this survey is to examine factors that influence on the perceived helpfulness in consumers' predicting its quality and safety when the country of origin (COO) of beef is declared. The data were analyzed that had collected from a consumer survey done in March 2006. 250 consumers living in Suncheon, Jeollanamdo were randomly selected as respondents. Eleven of them did not complete the survey material, so the total number of available samples were 239. All samples were estimated using proc logistic procedure of SAS package. The results indicate as follows: first, the levels of perceived helpfulness of COO in consumers' predicting beef quality and safety depend significantly on he age, the occupation, and the education level of demographic variables. Second, when analysing attitude variables to beef, the levels are significantly correlated with the respondents' ability to acquire information, their trust of information about beef, nd their interest about bovine spongiform encephalopathy(BSE). The proportional odds assumptions of models are not violated at p<0.05. Third, it is the gender, the age, and the education level of the respondents, and the respondents' ability to acquire information which significantly effect on the level of the perceived helpfulness of COO in predicting beef quality. Fourth, it is the consumer's age, their education level, and their trust of information about beef which statistically have a significant effect on the level of perceived helpfulness of COO in predicting beef safety.