• Communications for Statistical Applications and Methods
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• 제5권3호
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• pp.935-944
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• 1998

This paper investigates the problem of goodness of fit tests for no effect model. The proposed test statistic $Z_{mn}$ is obtained by multiplying constant on the model free curve estimation techniques. The small and large sample properties of$Z_{mn}$ are investigated and the good results of power studies for the proposed test are illustrated.

• 응용통계연구
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• 제11권2호
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• pp.257-268
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• 1998

역학연구에서 두 수준을 갖는 위험인자 X와 이항 반응변수 Y의 관계에 관심을 갖는 경우가 많다. 이 때 두 변수의 상관관계에 영향을 미칠 수 있는 인자 Z의 값을 제어함에 따라 X와 Y의 상관관계가 여전히 존재하는지를, 즉 X와 Y의 조건부 독립성을 검정할 필요가 있다 관측값의 수가 많지 않을 때, X와 Y의 조건부 독립성 검정을 위해 Mantel-Haenszel 검 정 이 널리 사용되고 있다. 하지 만 X와 Y의 상관관계가 Z의 수준에 따라 그 방향까지 변할 경우 이 검정은 낮은 검정력을 갖는다. 본 연구에서는 이 경우에 높은 검정력을 갖는 대안 검정통계량을 제안한다. 대안 검정통계량의 분포에 대해 알아보고 모의실험을 통해 Mantel-Haenszel 검정과 비교해 본다.

• Communications for Statistical Applications and Methods
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• 제4권3호
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• pp.891-901
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• 1997

The objective of this research is to investigate the problem of goodness of fit testing based on nonparametric density estimation with a data-driven smoothing parameter. The small and large smaple properties of the proposed test statistic $Z_{mn}$ are investigated with the minimizer $\widehat{m}$ of the estimated mean integrated squared error by the Diggle and Hall (1986) method.

• Communications for Statistical Applications and Methods
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• 제2권1호
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• pp.112-121
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• 1995

Let $p_1$ and $p_2$ be the proportions of two populations. To test the hypothesis $H_0 : p_1 = p_2$, we usually use the $x^2$ statistic, the large sample binomial statistic Z, and the Generalized Likelihood Ratio statistic-2log $\lambda$developed based on different mathematical rationale, respectively. Since testing the above hypothesis is equivalent to testing whether two populations follow the common Bernoulli distribution, one may also test the hypothesis by comparing 1 with the ratio of each density estimate and the hypothesized common density estimate, called comparison density, which was devised by Parzen(1988). We show that the above traditional test statistics ate actually estimating the measure of distance between the true densities and the common density under $H_0$ by representing them with the comparison density.

• 응용통계연구
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• 제34권6호
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• pp.863-874
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• 2021

FLSA는 총변동벌점을 이용해 구간별상수인 평균 구조를 구현하는 벌점모형으로 다중변화점 탐색을 위해 활용되고 있다. 한편, FLSA는 변화점 탐색에 있어서 점근적 일치성이 만족되지 않으므로 잡음의 크기가 0에 가깝게 수렴하는 경우에도 다수의 거짓 변화점이 식별될 수 있다는 단점이 있다. 이 연구에서는 이러한 FLSA의 문제점을 해결하기 위한 사후추론 방법으로 순열검정 방법을 제안한다. 단일변화점 모형과 관련된 순열검정 방법은 Antoch와 Hušková (2001)에 의해 제안된 바 있다. 이 연구에서는 Antoch와 Hušková (2001)의 검정절차를 확장하여 다중변화점 식별에 사용되는 FLSA와 결합함으로써 다중변화점 모형에 적용할 수 있는 순열검정절차를 제안한다. 모의실험 결과, 제안된 방법은 z-검정과 CUSUM 통계량의 극한분포에 기반을 둔 검정방법에 비해 전반적으로 우수하였으며 거짓 변화점의 식별에 유용함을 확인할 수 있었다.

• 한국수학교육학회지시리즈A:수학교육
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• 제45권2호
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• pp.145-154
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• 2006

The main purpose of this study is to investigate the effect of departures from normality and equal variance on the two-sample test when the variances are unknown. We have found that type I error brought about a little bit change which is ignorable in relation to kurtosis. But the change of type I error was mainly based on the skewness of the parent population. In introductory statistics classes where data analysis includes techniques for detecting skewness of two populations, we recommend the two-sample t-test when maximal skewness of two populations is smalter than the value 4 when the variances seem equal. Furthermore, our simulations reveal that the two-sample t-test appears somewhat more robust than that of z-test if the assumption of equal variance is satisfied. In the case of unequal variance, the two-sample t-test appears somewhat more robust provided the t-statistic using Satterthwaite's approximate degrees of freedom.

• 한국산학기술학회논문지
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• 제20권7호
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• pp.218-227
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• 2019

본 연구의 목적은 밸런스 테이핑요법이 농촌 여성노인의 무릎통증과 일상활동장애 개선에 미치는 영향을 확인하는 것이다. 연구설계는 비동등성 대조군 전후설계를 이용한 유사실험연구이다. 자료수집 기간은 2017년 1월 19일부터 4월 14일까지이며, 연구 대상은 농촌지역인 Y시에 소재한 경로당을 방문한 65세 이상 여성노인 54명으로 실험군 26명, 대조군 28명이다. 자료는 밸런스 테이핑 적용 전과 24시간 후에 무릎통증과 일상활동장애 정도를 조사하였고, 수집된 자료는 PASW Statistics 23.0 프로그램을 이용하여 $X^2-test$, Shapiro-Wilk test, Mann-Whitney U test로 분석하였다. 본 연구결과 24시간 동안 밸런스 테이핑요법을 적용받은 실험군이 대조군에 비해 무릎통증(Z=-6.658, p<.001)과 일상활동장애(Z=-3.466, p=.001) 정도가 유의하게 감소하였다. 일상활동장애의 하위영역 중에서는 일어서기(Z=-2.860, p=.004), 일상적 활동하기(Z=-2.629, p=.009), 걷기(Z=-3.868, p<.001)와 몸단장하기(Z=-2.049, p=.040)의 장애정도가 유의하게 감소하였고, 물건 쥐기(Z=-.542, p=.588)와 팔 뻗치기(Z=-.416, p=.678)는 유의한 차이가 없었다. 본 연구결과 밸런스 테이핑요법은 농촌 여성노인의 무릎통증 감소와 일어서기, 일상적 활동하기, 걷기, 몸단장하기와 같은 일상활동장애 개선에 효과적인 간호중재로 확인되었다. 추후 대상자의 사전 통증정도, 밸런스 테이핑 적용횟수, 24시간이상 적용에 따른 장기효과, 다른 신체 부위 적용에 따른 효과 확인과 밸런스 테이핑 적용이 통증의 감소로 우울감 등 심리 건강에도 효과적인지 파악하는 후속연구, 그리고 밸런스 테이핑 적용이 통증감소와 일상활동장애를 개선시키는 생리학적 기전을 밝히는 연구를 제언한다.

• 지역사회간호학회지
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• 제16권3호
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• pp.282-288
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• 2005

Purpose: This study was to verify the effects of a smoking cessation program for adolescents. Method: This study was designed to use one group with one pre-test and two post-tests. One post-test was done immediately after the completion of the program and the other after eight weeks. The subjects were 21 male high school students who were smokers when this study was carried out. The smoking cessation program consisted of 5 sessions with smoking cessation education and e-mail service after the program. Variables in this research were nicotine dependency (using Fagerstrom Tolerance Questionnaire) and self-efficacy. Data were analyzed by descriptive statistics and Wilcoxon signed rank test. Results: Immediately after the program and eight weeks later, nicotine dependency for continuous smokers decreased significantly (after the program: Z=-2.319, p=.020, eight weeks later: Z=-1.999. p=.046) and self-efficacy increased significantly (after program: Z=-3.024. p=.002. eight weeks later: Z=-2.381. p=.017). Conclusions: The smoking cessation program was effective in decreasing nicotine dependency in the continuous adolescent smokers and in increasing their self-efficacy, Further study needs to be made with a lager number of smoking adolescents using control group design.

• Child Health Nursing Research
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• 제27권1호
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• pp.13-23
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• 2021

Purpose: This study aimed to develop a mobile-based self-management health alarm (MSHA) program for modifying obese children's lifestyle based on the information-motivation-behavioral skills (IMB) model and to test its feasibility. Methods: A methodological study for the development of the MSHA program and pilot study with a one-group pretest-posttest design for feasibility testing was conducted. The MSHA program was designed to provide obesity-related information (I), monitor daily diet and exercise, provide motivational text messages (M), and enhance healthy diet and exercise skills (B) via a mobile-based web platform. In the feasibility test, six obese children participated in the 4-week program, and the number of days per week that they achieved their goals and differences in metabolic components were assessed. Data were analyzed using descriptive statistics and the Wilcoxon signed-rank test. Results: Participants successfully achieved their diet and exercise goals≥5 days per week. Body mass index (z=-1.99, p=.046), waist circumference (z=-2.20, p=.028), and triglyceride levels (z=-2.21, p=.027) significantly decreased. Conclusion: The MSHA program showed positive effects on health behaviors and metabolic syndrome risk. The program may be effective in improving metabolic syndrome in obese children by promoting self-health management behaviors.

• Communications for Statistical Applications and Methods
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• 제24권2호
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• pp.129-142
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• 2017

In this paper we consider the problem of the model selection/discrimination among three different positively skewed lifetime distributions. Lindley, Weibull, and gamma distributions have been used to effectively analyze positively skewed lifetime data. This paper assesses how much closer the Lindley distribution gets to Weibull and gamma distributions. We consider three techniques that involve the likelihood ratio test, asymptotic likelihood ratio test, and minimum Kolmogorov distance as optimality criteria to diagnose the appropriate fitting model among the three distributions for a given data set. Monte Carlo simulation study is performed for computing the probability of correct selection based on the considered optimality criteria among these families of distributions for various choices of sample sizes and shape parameters. It is observed that overall, the Lindley distribution is closer to Weibull distribution in the sense of likelihood ratio and Kolmogorov criteria. A real data set is presented and analyzed for illustrative purposes.