• Journal of Korean society of Dental Hygiene
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• v.21 no.5
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• pp.595-600
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• 2021

Objectives: For postmenopausal women who participated in the 2019 National Health and Nutrition Examination Survey, we aimed to provide basic data for oral health management interventions and oral policies for each life cycle of postmenopausal women by identifying the relationship between physical activity and depression on oral health behavior and awareness symptoms. Methods: The participants of this study were 1,628 menopausal women, and their general characteristics, physical activity, depression, and oral health behavior and awareness symptoms were investigated. This study used the complex sample frequency analysis, complex sample 𝞆² test, and logistic regression analysis method, which is a sample design of the National Health and Nutrition Examination Survey. Results: The factors influencing physical activity were the use of oral hygiene device and chewing difficulty. and the influencing factors of depression experience were pain and chewing difficulty. Conclusions: As a result, physical activity and depression experience should be utilized by developing and oral health program for the promotion of oral health in postmenopausal women.

• Communications for Statistical Applications and Methods
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• v.10 no.2
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• pp.553-566
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• 2003

In many cases, the measurement error variances may be functions of the unknown true values or related covariates. This paper considers design-based estimators of the parameters of these variance functions based on the within-unit sample variances. This paper devotes to: (1) define an error scale factor $\delta$; (2) develop estimators of the parameters of the linear measurement error variance function of the true values under large-sample and small-error conditions; (3) use propensity methods to adjust survey weights to account for possible selection effects at the replicate level. The proposed methods are applied to medical examination data from the U.S. Third National Health and Nutrition Examination Survey (NHANES III).

• The Korean Journal of Applied Statistics
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• v.31 no.5
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• pp.587-597
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• 2018

Procedures, such as sampling technique, survey method, and questionnaire preparation, are required in order to obtain sample data in accordance with the purpose of a survey. An important procedure is the decision of the sample size formula. The sample size formula is determined by setting the target error and total cost according to the sampling method. In this paper, we propose a sample size formula using population changes over time, estimation error of the previous time and response rate of past data when the target error and the expected response rate are given in the simple random sampling. In actual research, we use estimators that apply complex weights in addition to design-based weights. Therefore, we induce a sample size formula for estimators using design-based weights and nonresponse adjustment coefficients, that can be a formula that reflects differences in response rates when survey methods are changed over time. In addition, we use simulations to compare the proposed formula with the existing sample size formula.

• Journal of The Korean Society of Integrative Medicine
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• v.12 no.2
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• pp.187-195
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• 2024

Purpose : Many studies have confirmed the relationship between physical exercise, chronic diseases, and quality of life, but few of those studies were limited to aerobic exercise. Above all, no research has confirmed the relationship between aerobic exercise and the oral health. This study is significant because it is the first study to confirm the relationship between aerobic exercise, which is practiced more frequently than other exercises, and oral health in adults. Through this study, we hoped to confirm the complex impacts of aerobic exercise on health-related quality of life, oral health-related behavior, and oral health status in adults and to use these impacts as basic data on the importance of aerobic exercise. Methods : In this study, the following analysis was conducted based on a complex sample design that applied stratification variables, cluster variables, and weights using SPSS version 21.0. Complex sample cross-analysis was conducted to identify general characteristics according to aerobic physical activity practice, and oral health-related characteristics according to the aerobic physical activity practice rate. Then, complex sample logistic regression analysis was conducted to determine the effect of aerobic physical activity practice on oral health-related characteristics. During the statistical analysis, missing values were treated as valid values, and the statistical significance level was set at .05. Results : Aerobic physical activity practice was 1.39 times higher among the respondents who brushed their teeth after lunch (p<.001), 1.43 times higher among those who used dental floss (p<.001), 1.24 times higher among those who used mouthwash (p=.040), and 1.37 times higher was among those who had not experienced dental treatment (p=.040), which were statistically significant differences. Conclusion : This study found that when an individual's health status is maintained, positive oral health behavior can be achieved by paying attention to oral health, and this appears to contribute to improving oral health.

• Journal of the Korean Data and Information Science Society
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• v.16 no.3
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• pp.609-620
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• 2005

In the secondary data analysis for categorical data, situations often arise in which the estimated cell variances are available, but not the full matrix of variances. In this case researchers are often inclined to use Pearson-type test statistics for homogeneity. However, for a complex sample observed cell proportions are not distributed as multinomial and Pearson-type test statistic generally is not distributed asymptotically as chi-square distribution. This paper evaluates powers for Wald test and Pearson-type test and the first order corrected test of Pearson-type test for homogeneity. The resulting power curves indicate that as the misspecification effect increases, the amount of inflation of significance level and the loss of power Pearson-type test are getting more severe.

• Journal of Preventive Medicine and Public Health
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• v.46 no.2
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• pp.96-104
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• 2013

Objectives: The inherent nature of the Korean National Health and Nutrition Examination Survey (KNHANES) design requires special analysis by incorporating sample weights, stratification, and clustering not used in ordinary statistical procedures. Methods: This study investigated the proportion of research papers that have used an appropriate statistical methodology out of the research papers analyzing the KNHANES cited in the PubMed online system from 2007 to 2012. We also compared differences in mean and regression estimates between the ordinary statistical data analyses without sampling weight and design-based data analyses using the KNHANES 2008 to 2010. Results: Of the 247 research articles cited in PubMed, only 19.8% of all articles used survey design analysis, compared with 80.2% of articles that used ordinary statistical analysis, treating KNHANES data as if it were collected using a simple random sampling method. Means and standard errors differed between the ordinary statistical data analyses and design-based analyses, and the standard errors in the design-based analyses tended to be larger than those in the ordinary statistical data analyses. Conclusions: Ignoring complex survey design can result in biased estimates and overstated significance levels. Sample weights, stratification, and clustering of the design must be incorporated into analyses to ensure the development of appropriate estimates and standard errors of these estimates.

• Journal of the Korean Data and Information Science Society
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• v.28 no.2
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• pp.443-449
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• 2017

Estimation of population proportion like the distribution rate of LED TV and the prevalence of a disease are often estimated based on survey sample data. Population proportion is generally considered as a special form of population mean. In complex sampling like stratified multistage sampling with unequal probability sampling, the denominator of mean may be random variable and it is estimated like ratio estimator. In this research, we examined the estimation of distribution rate based on stratified multistage sampling, and determined some numerical outcomes using stratified random sample data with about 25% of missing observations. In the data used for this research, the survey weight was determined by deterministic way. So, the weights are not random variable, and the population distribution rate and its variance estimator can be estimated like population mean estimation. When the weights are not random variable, if one estimates the variance of proportion estimator using ratio method, then the variances may be inflated. Therefore, in estimating variance for population proportion, we need to examine the structure of data and survey design before making any decision for estimation methods.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.18 no.33
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• pp.93-102
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• 1995

In this study we are concerned with the diagnostics method of cross-classified categorical data using logistic regression model of binary response models for cell proportions. under this model, we could examine the goodness-of-fit of the models using Pearson's $x^2$test statistic and likelihood ratio statistic. Under this model, these statistics are assumed that sample survey schemes are with replacement sampling model. But these statistics are often inappropriate for analysing contingency tables consists of complex sampling schemes obtained sample survey data. In this study we are examined diagnostics procedures detecting any outlying cell proportions and influential observations on design space in logistic regression modeltake account of the survey design effects.

• Survey Research
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• v.11 no.1
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• pp.123-144
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• 2010

In new sample design for Korea Housing Survey to research about housing policy, total strata are forty five because individual results of sixteen regions are estimated. The sample size is determined by sample errors of several variables which are the living area, family income, householder income, and living expenses. The sample size of each region is determined by relative standard error of existing result, and the strata sample size is to use the square root proportion allocation. Enumeration districts are sampled by the probability proportion to size systematic sampling in proportion to the enumeration district size, and the systemic sampling to use assortment characteristics. We considered a new apartment complex because of variation reflections which are rebuilder and redevelopment of houses. To get estimators of mean and variance, we used the design weighting, non-response adjusting, and post-stratification. In order to consider estimation efficiency, we calculate the design effect using estimators of variance.

• Journal of Society of Preventive Korean Medicine
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• v.24 no.1
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• pp.27-35
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• 2020

Objectives : The purpose of study was estimation of adverse events [AEs] scale relating herbal medicine in Korea using Korean Medicine Utilization and Herbal Medicine Consumption Survey (National statistics No. 117087). Methods : Using microdata of Korean Medicine Utilization and Herbal Medicine Consumption Survey 2017, the number of inpatients and outpatients who experienced AEs was calculated. The microdata included AEs of all treatment methods that have been performed by visiting Korean medical institutions for one year, so set up the data into three models; model A (in case all treatments were only herbal medicine for one year), model B (in case herbal medicines were a part of all treatment methods in 1 year), model C (in case herbal medicines were a part of treatment methods at least one time in 1 year). The proportion of patients who experienced AEs during the last 1 year was calculated and then, the number of AEs relating herbal medicine was estimated. Results : A total of 1,010 outpatients and 904 inpatients were included in Korean Medicine Utilization and Herbal Medicine Consumption Survey 2017. The number of patients who had experienced AEs in the past 1 year was 0 in the model A, 9 in the model B (5 for outpatients, 4 for inpatients), and 19 in the model C (10 for outpatients, 9 for inpatients). By consideration for the complex sample survey, estimating the number of AEs relating herbal medicine, the model A was 0, the model B was 36,457 patients (0 to 75,526 patients), and the model C was 84,830 patients (26,314 to 143,347 patients). Conclusion : From the results of this study, it was possible to estimate the scale of AEs relating herbal medicines in Korea, suggesting that it is necessary to understand the actual condition of AEs and establish its management system.