• Studies on Korean Youth
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• v.30 no.3
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• pp.5-32
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• 2019

The purpose of this study was to compare methods of model specification to control covariates in mediation analysis with structural equation modeling. In order to do this, monte carlo simulation was conducted. In this study, five models were compared, and each model was evaluated based on both the accuracy of estimates and model fit. The results showed that when the NC(Non Control) model was applied, model fit was good, however, estimates of mediation effect, direct effect, and total effect were all found to be biased. In terms of both the OC(Outcome Control) model and the COC(Correlated Outcome Control) model, estimates of mediation effect and total effect were biased. Additionally, model fit was found to be unacceptable in both the OC model and the COC model. When the MOC(Mediator-Outcome Control) model was applied, the estimates were unbiased, but under certain conditions, model fit was unacceptable. In the CMOC model, estimates of mediation effect, direct effect, and total effect were all unbiased, and model fit was good. Based on these results, for the purposes of controlling covariates in mediation analysis, the CMOC model was suggested as being the most appropriate.

• The Korean Journal of Applied Statistics
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• v.24 no.1
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• pp.161-167
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• 2011

The primary variables are often systematically related to other influences apart from drug effect. For instance, there may be relationships to covariates such as health conditions or prognostic factors. When a $2{\times}2$ crossover experiment for bioequivalence is designed, the statistical adjustment for the influence of covariates should be considered if some covariates influence the drug effect. Statistical inference for assessing average bioequivalence for a $2{\times}2$ crossover design with covariates is given and an illustrated example is presented with discussion.

• Journal of the Korean Chemical Society
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• v.46 no.4
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• pp.377-384
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• 2002

In this study, the effect of cooperative computer-assisted instruction upon students' conceptual under-standing,application ability, and learning motivation were investigated by a previous achievement level. The treatment and the control groups (2 classes) were selected from a middle school in Seoul, and taught about the motion of molecule for 5 class periods. Prior to the instructions, a learning motivation test was administered and used as covariate. The scores of a previous achievement test were also used as covariate. The scores of the mid-term science examination were used as blocking variable. After the instructions, the conceptions test, the application test, and the learning motivation test were administered. Two-way ANCOVA results revealed that there were no significant differences in the scores of the con-ceptions test and the application test. However, the scores of the treatment group were found to be significantly higher than those of the control group in the learning motivation test.

• Journal of the Korea Society of Computer and Information
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• v.16 no.12
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• pp.297-304
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• 2011

This study was to analyze the learning effectiveness of multi-media based class by comparing with traditional classroom method. The "Distribution Working Subject" course that is one of the required courses of Vocational high school was selected and its contents were digitalized on MS Powerpoint for multi-media based class. The thirty students were sampled for each experimental and control groups. The homogeneity and learning achievement of sample groups were tested for experiment. Same teacher took the classes of two groups and delivered same contents of course. Only difference between two groups was the delivery method, one is traditional classroom teaching method and the other was the multi-media based class. The learning achievements and satisfaction of sample were post-tested in order to analyze the learning effectiveness by comparing two teaching methods. The results showed that there was a significant difference between experimental and control group in learning achievement after ANCOVA controlled pre-test as covariance(F=5.08, p<.05). It means that the learning achievement of multi-media based class was higher than that of traditional classroom group. The results also showed that a significant difference in students' satisfaction between two groups (t=5.57, p<.001). This study concluded that using multi-media in class could produce more learning achievements and satisfaction of students than traditional classroom method.

• Journal of Convergence for Information Technology
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• v.9 no.10
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• pp.133-143
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• 2019

The purpose of this paper was to analyze the differences in executive function according to type of early English learning experience. The subjects were 75 5-years-old who had immersive early English learning in language school, and daycare center. The measurement tools were stroop, DCCST, memorize numbers, pattern fluency, and maze. We conducted covariance analysis with total intelligence as the covariates. In the results, there were significant differences in attention control and cognitive flexibility, but weren't significant differences in information processing and goal setting according to type of early English learning experience. This study suggests that experience of immersive early English learning positively affected attention control and cognitive flexibility, and didn't affect information processing and goal setting.

• Journal of East-West Nursing Research
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• v.14 no.1
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• pp.78-86
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• 2008

본 연구는 여대생의 건강증진행위를 설명하기 위하여, 문헌고찰을 통해 가설적 모형을 도출하고, 여대생을 대상으로 건강증진행위를 횡단적으로 조사하여 모형의 적합성과 모형에서 제시된 가설을 검증하는 서술적 상관관계 연구이다. 연구에 사용된 변수는 건강증진행위와 관련된 선행 문헌의 고찰을 근거로 선정되었으며, 총 280명의 자료가 최종 분석에 이용되었다. 설문지는 Pender의 건강증진모형을 기초로 하여 개발하였으며, 조정요인 5문항, 건강상태 지각 3문항, 건강 통제위 4문항, 자아 존중감 5문항, 건강증진 행위 24문항의 총 41문항으로 구성하여 사용하였다. 개발된 항목에 대하여 간호대학생들을 대상으로 사전 조사를 실시하여 최종적인 설문지를 완성하였다. 본 연구모형에 대한 구성개념의 파악을 위해서 탐색적 요인분석을 실시하였고, 측정항목에 대한 요인별 단일 차원성 확인 및 통계적 검정을 위해 확인적 요인분석을 실시하였다. 연구의 가설검증을 위해 공변량 구조분석을 실시하였다. 모형의 적합도는 카이제곱은 244.04(자유도=121, p<0.001), GFI=0.91, CFI=0.97, NNFI=0.96, RMSR= 0.022으로 나타났다. 분석결과 여대생의 자아존중감과 내적통제위는 건강상태지각 및 건강증진행위에 유의한 영향을 미치는 요인으로 확인되었으며, 여대생의 건강상태지각은 건강증진행위에 유의한 영향을 미치는 것으로 나타났다.

• The Journal of the Korea institute of electronic communication sciences
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• v.12 no.5
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• pp.965-976
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• 2017

The purpose of this study was to investigate how the Peer counseling program in on-offline would effect university students on their self-esteem and self-efficacy. In order to achieve this purpose, ten participants were in the experimental group and the other ten were in the control group. The subjects in the experimental group receive to the peer counseling program training for 120 minutes once a week for 10 weeks. The next day, practiced counseling online The data were analyzed by using t-test and ANCOVA. As the participants of the Peer counseling program reported that they experienced significant difference of improvement on their self-esteem(F=13.258, p<.01) and self-efficacy(F=15.565, p<.01) than those were in the control group. The Peer counseling program suggested that expected to positive effects it would help improve university freshmen students' self-esteem and self-efficacy.

• Journal of The Korean Association For Science Education
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• v.19 no.2
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• pp.229-238
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• 1999

This study investigated the influences of Vee diagram and regulative metacognitive learning strategies upon 6th-graders' achievement, difficulty toward science lesson, self-efficacy, and learning approach. The Vee diagram and regulative metacognitive learning strategies were modified in a pilot study. Before instruction, an achievement test was administered, and its score was used as a blocking variable. A previous science grade was used as a covariate for post-achievement. Tests of difficulty toward science lesson, self-efficacy, and learning approach were also administered, and the test scores were used as covariates. After instruction, a researcher-made achievement test and post-tests of the above variables were administrated. Two-way ANCOVA results revealed that although there were no significant differences in the achievement test scores, the application subtest scores of the two treatment groups were significantly higher than those of the control group. There were no significant differences in the difficulty toward science lesson and learning approach, but self-efficacy scores for the students with Vee diagram and regulative metacognitive learning strategies were significantly higher than those of the other groups. The perceptions of the students using Vee diagram were also analyzed.

• Journal of Science Education
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• v.35 no.1
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• pp.68-79
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• 2011

The purpose of this study was to investigate the recognition of middle school students on 'Thinking Science' activities and the influence on the understanding of the gas particles behavior concepts. For this study 125 students of four classes first grade in middle school were divided into two groups, the experimental and the control group. The SRT II test was carried out to identify the cognitive level of the students. The logical factors, needed to understand of the gas particles behavior concepts, were extracted. And the 9 'Thinking Science' activities designed to develop these factors were chosen and then implemented to the students of the experimental group. After the lesson for the gas particles behaviors, the achievement test of understanding of the gas particles behavior concepts and the survey of the students' recognition on 'Thinking Science' activities were administered. According to the results of the achievement test, there was not significant difference between the two groups on the whole. But only mature concrete operational students in the experimental group got high scores than those in the control group in analyzing the effect size. According to the results of the ANCOVA analysis, there was significant difference between the two girls' group. When students in the experimental group had a positive perceptions about 'Thinking Science' activities, they got higher achievement scores. This implied that there was a correlation between perception about 'Thinking Science' activities and their achievement in the gas particles behavior concepts. Especially, students with positive perception in mature concrete operational period got higher scores in science achievement. After the 'Thinking Science' activities, there was a high perceptions about improving in scientific thinking.

• Journal of vocational education research
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• v.29 no.3
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• pp.247-263
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• 2010

The purpose of this study is making the career education program related to the subject, Manual Training and Home Economics, to present the effective guidance and to improve career maturity of students about the unit, "Making a choice of career and Job ethics" of middle school senior's course. In order to estimate this program, 60 students of 2 classes were chosen as research subjects among middle school seniors and each of classes was divided into two groups, an experimental group and a control group. After the experimental group was trained the career education program related to Manual Training and Home Economics for 15 sessions, the effect was verified by comparing tests before and after program execution. In order to prove effects of the program. Each grade of both the experimental group and the control group was taken analysis of covariance (ANCOVA). Result of the program experiment is following. First, after executing the career education program related to Manual Training and Home Economics to the experimental group, participants showed that both attitude and ability for career maturity were improved in each sub-factor field of the career maturity as a result of tests before and after program execution. Second, in program satisfaction estimation, most of students had a positive attitude and in every time satisfaction, they made high estimation on the program, especially including the proper level of students and interesting activities. Finally, the final program was completed based on the result of effect analysis of the program.