• Communications for Statistical Applications and Methods
• /
• v.2 no.2
• /
• pp.155-165
• /
• 1995

반복측정자료의 분석을 위해 제안된 Liang and Zeger(1986)의 회귀모형은 일반화추정식(generalized estimationg equations, GEE)을 이용하여 모형의 모수를 추정한다. 이 모형은 반복측정된 반응변수와 설명변수들과의 관계를 추정하는 것이 주된 목적이기 때문에 회귀모수는 중요한 모수로 간주되나 산포모수는 중요하지 않은 장애모수(nuisance parameters)로 간주된다. 일반적으로 GEE 분석에서 회귀모수의 추정량은 산포모수에 상관없이 일치적(consistent)으로 얻어진다고 알려져 있다. 그러나 본 논문에서는 포아송분포를 따르는 반복측정자료에 대한 사례연구와 모의 실험을 통해서 일반적으로 믿어져왔던 것과는 달리 GEE 방법이 산포모수에 민감하게 영향을 받고 있음을 보였다. 특히 산포모수의 값이 일정하지 않은 경우에는 GEE 방법이 산포모수에 민감 하게 영향을 받고 있음을 보였다. 특히 산포모수의 값이 일정하지 않은 경우에는 GEE 방법에서 밝혀진 회귀모수 추정량의 일치성에도 문제가 발생할 수 있음을 보였다.

• The Korean Journal of Applied Statistics
• /
• v.17 no.3
• /
• pp.547-556
• /
• 2004

This paper consider the testing problem of variance component for the unbalanced two-way error component model with nuisance parameter. We derive the one-sided LM test statistic for testing zero individual(time) effects assuming that the other time-specific(individual) effects are present. Using the Monte Carlo experiments, the computational more demanding LR test slightly underestimates the nominal size and has the low powers relative to LM test statistic.

• The Journal of the Korea Contents Association
• /
• v.18 no.8
• /
• pp.561-572
• /
• 2018

This study the awareness and the demands of the parents on the communication level for social participation of the youth with developmental disability were identified and investigated the relation on client's age, detection time of the condition, disability grades, handicapped types, speech therapy period. For the non-parametric test, Man-Whitney U test, and Kruskal-Wallis test were performed and for post-hoc test, Scheffe test was performed. The results of this study was that the significant difference was found in the awareness and the demand of the communication level of the youth with developmental disability according to the age of children, time of discovery, disability grade, type of disability and speech therapy period. In conclusion, the speech therapy for the youth with developmental disability should be made in the dimension of communication for the purpose of social participation. The follow-up research to emphasize the social support and the institutional backup will be required.

• The Korean Journal of Applied Statistics
• /
• v.20 no.3
• /
• pp.449-458
• /
• 2007

Bipolar disorder, also known as manic-depressive illness, is a brain disorder that causes unusual shifts in person's mood, energy, and ability to function. Compared with manic episode, the depression episode causes more serious results such as restless, loss of interest or pleasure, or thoughts of death or suicide and the cure rate of depression episode is lower than that of manic episode. Furthermore, a long term use of antidepressants in bipolar patients may result in manic episode. Our interest is to investigate the effect of antidepressant on switch of moods of bipolar patients and to estimate the transition probabilities of switch between moods, depression and (hypo) manic. In this study, three approaches are applied in terms of multi state model. Parametric model is applied using left censoring data and nonparametric model is implemented under illness-death model with counting process. In order to estimate the effect of covariates, a multiplicative model is used. These all methods have similar results.

• Journal of the Korean Data and Information Science Society
• /
• v.17 no.3
• /
• pp.707-716
• /
• 2006

When the regression function is discontinuous at a point, the variance function is usually discontinuous at the point. In this case, we had better propose a test for the existence of a discontinuity point with the regression function rather than the variance function. In this paper we consider that the variance function only has a discontinuity point. We propose a nonparametric test for the existence of a discontinuity point with the second moment function since the variance function and the second moment function have the same location and jump size of the discontinuity point. The proposed method is based on the asymptotic distribution of the estimated jump size.

• The Korean Journal of Applied Statistics
• /
• v.16 no.1
• /
• pp.117-128
• /
• 2003

The goal of non-inferiority experiments is to show that the new treatment is not inferior to the standard experiment. In this paper we compare the three methods of variance estimation used in the unconditional exact tests of two proportions. The size and power of the tests with each variance estimation method are compared using complete enumeration.

• The Korean Journal of Applied Statistics
• /
• v.15 no.1
• /
• pp.187-199
• /
• 2002

When the sample size is small, exact tests are often employed because the asymptotic distribution of the test statistic is in doubt. The advantage of exact tests is that it is guaranteed to bound the type I error probability to the nominal level. In this paper we review the methods of constructing exact tests, the algorithm and commercial software. We also examine the difference between exact p-values obtained from exact tests and true p-values obtained from the true underlying distribution.

• The Korean Journal of Applied Statistics
• /
• v.20 no.2
• /
• pp.281-290
• /
• 2007

Linear estimator, a weighted sum of the sample observation, is commonly adopted to estimate the finite population parameters such as population totals in survey sampling. The weight for a sampled unit is often constructed by multiplying the base weight, which is the inverse of the first-order inclusion probability, by an adjustment term that takes into account of the auxiliary information obtained throughout the population. The linear estimator using the weight adjustment is often more efficient than the one using only the bare weight, but its valiance estimation is more complicated. We discuss variance estimation for a general class of weight-adjusted estimator. By identifying that the weight-adjusted estimator can be viewed as a function of estimated nuisance parameters, where the nuisance parameters were used to incorporate the auxiliary information, we derive a linearization of the weight-adjusted estimator using a Taylor expansion. The method proposed here is quite general and can be applied to wide class of the weight-adjusted estimators. Some examples and results from a simulation study are presented.

• Journal of the Korean Academy of Child and Adolescent Psychiatry
• /
• v.10 no.1
• /
• pp.43-49
• /
• 1999

Objectives：One of the most common developmental problems is communication disorder in which a child appears normal in every way but who has failed to begin speaking or speaks very little. A few studies have examined the temperamental characteristics of children with communication disorders. This study was to investigate the temperamental characteristics of Korean children with communication disorders. Methods：The parents of 20 Korean children with communication disorders and the parents of 50 normal control children, the age of both groups ranges from 3 to 7, completed Korean version of Parental Temperamental Questionnaire developed by Thomas and Chess. Children with a pervasive developmental disorder, mental retardation, or speech-motor or sensory deficit were excluded. The scores of each temperamental scale of two groups and the diagnostic clusters of two groups were compared. Results：The children with communication disorders were characterized by lower mood scores and higher intensity of reaction scores than normal controls. The two groups showed no significant correlation in terms of the temperamental diagnostic clusters. Conclusion：This findings suggest the existence of a distinct temperamental profile of the children with communication disorders. Early detection of the profile may be of great value for parents in understanding the developmental characteristics of the children with communication disorders and in providing appropriate parenting approaches.

• Journal of the Korea Convergence Society
• /
• v.12 no.12
• /
• pp.427-434
• /
• 2021

This study was conducted to investigate the job-performance of manual wheelchair post-management and to find out the relationship between job-performance and vocational ability of people with developmental disabilities. In this study, situational evaluation and vocational evaluation were conducted for 9 subjects participated in the vocational training program about manual wheelchair post-management. The data was analyzed by non-parametric statistical processing. As a result, the job-performance was an average of 80.87%. The job-performance had a positive correlations with visual closure, kinesthetic integration, and basic concepts(p<.05). The relationship between job-performance and vocational abilities can be used as basic data for vocational training program and job assignment. It is expected to be useful of spreading the post-management job for assistive technology devices in the local community activated through the convergence of assistive technology and vocational rehabilitation.