• Communications for Statistical Applications and Methods
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• v.19 no.5
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• pp.721-729
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• 2012

Various methods control the influence of a covariate on a response variable. These methods are analysis of covariance(ANCOVA), RANK ANCOVA, ANOVA of (covariate-adjusted) residuals, and Kruskal-Wallis tests on residuals. Covariate-adjusted residuals are obtained from the overall regression line fit to the entire data set that ignore the treatment levels or factors. It is demonstrated that the methods on covariate-adjusted residuals are only appropriate when the regression lines are parallel and covariate means are equal for all treatments. In this paper, we proposed the new nonparametric method on the ANCOVA model, as applying joint placement in a one-way layout on residuals as described in Chung and Kim (2007). A Monte Carlo simulation study is adapted to compare the power of the proposed procedure with those of the previous procedure.

• The Korean Journal of Applied Statistics
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• v.27 no.2
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• pp.227-237
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• 2014

We use the regression model with the indicator variables in the case that we use qualitative variables as some predictor variables in regression analysis. We use the ANCOVA(Analysis of Covariance) model when comparing the response variable among groups while statistically controlling for variation in the response variable caused by a variation in the covariate. DD-plot can be used as a graphical exploratory data analysis tool before the confirmatory data analysis. With the DD-plot, we can discriminate the difference of groups in the regression model with the indicator variables or the ANCOVA model at a glance. Making DD-plot does not demand the statistical model assumption about error terms in regression model. Several examples show the usefulness of DD-plots as a graphical exploratory data analysis tool for the regression analysis.

• Asian-Australasian Journal of Animal Sciences
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• v.30 no.6
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• pp.765-772
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• 2017

Objective: This study examines the genetic factors influencing the phenotypes (four economic traits:oleic acid [C18:1], monounsaturated fatty acids, carcass weight, and marbling score) of Hanwoo. Methods: To enhance the accuracy of the genetic analysis, the study proposes a new statistical model that excludes environmental factors. A statistically adjusted, analysis of covariance model of environmental and genetic factors was developed, and estimated environmental effects (covariate effects of age and effects of calving farms) were excluded from the model. Results: The accuracy was compared before and after adjustment. The accuracy of the best single nucleotide polymorphism (SNP) in C18:1 increased from 60.16% to 74.26%, and that of the two-factor interaction increased from 58.69% to 87.19%. Also, superior SNPs and SNP interactions were identified using the multifactor dimensionality reduction method in Table 1 to 4. Finally, high- and low-risk genotypes were compared based on their mean scores for each trait. Conclusion: The proposed method significantly improved the analysis accuracy and identified superior gene-gene interactions and genotypes for each of the four economic traits of Hanwoo.

• Journal of applied mathematics & informatics
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• v.32 no.3_4
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• pp.343-357
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• 2014

In many non-life insurance applications past data are given in a form known as the run-off triangle. Smoothing such data using parametric crisp regression models has long served as the basis of estimating future claim amounts and the reserves set aside to protect the insurer from future losses. In this article a fuzzy counterpart of the Hoerl curve, a well-known claim reserving regression model, is proposed to analyze the past claim data and to determine the reserves. The fuzzy Hoerl curve is more flexible and general than the one considered in the previous fuzzy literature in that it includes a categorical variable with multiple explanatory variables, which requires the development of the fuzzy analysis of covariance, or fuzzy ANCOVA. Using an actual insurance run-off claim data we show that the suggested fuzzy Hoerl curve based on the fuzzy ANCOVA gives reasonable claim reserves without stringent assumptions needed for the traditional regression approach in claim reserving.

• The Korean Journal of Applied Statistics
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• v.30 no.3
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• pp.427-439
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• 2017

Quade (1967) proposed RANK ANCOVA, which is a nonparametric method to test differences between treatments when there are covariates. Hwang and Kim (2012) also proposed a joint placement test on covariate-adjusted residuals. In this paper, we proposed a new nonparametric method to control the effect of covariate on a response variable that uses linear statistics on covariate adjusted-residuals. The score function used in the linear statistics was proposed by Jeon and Kim (2016). Monte Carlo simulation is also conducted to compare the empirical powers of the proposed method with previous methods.

• Communications for Statistical Applications and Methods
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• v.24 no.3
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• pp.241-254
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• 2017

Drawing a sample can be costly or time consuming in some studies. However, it may be possible to rank the sampling units according to some baseline auxiliary covariates, which are easily obtainable, and/or cost efficient. Ranked set sampling (RSS) is a method to achieve this goal. In this paper, we propose a modified approach of the RSS method to allocate units into an experimental study that compares L groups. Computer simulation estimates the empirical nominal values and the empirical power values for the test procedure of comparing L different groups using modified RSS based on the regression approach in analysis of covariance (ANCOVA) models. A comparison to simple random sampling (SRS) is made to demonstrate efficiency. The results indicate that the required sample sizes for a given precision are smaller under RSS than under SRS. The modified RSS protocol was applied to an experimental study. The experimental study was designed to obtain a better understanding of the pathways by which positive experiences (i.e., goal completion) contribute to higher levels of happiness, well-being, and life satisfaction. The use of the RSS method resulted in a cost reduction associated with smaller sample size without losing the precision of the analysis.

• The Journal of the Korea Contents Association
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• v.14 no.8
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• pp.505-516
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• 2014

This study was aimed at identifying the influence of Creative Thinking Filtering Mode program in international gifted program: how much it influences to improve the cognitive domains of creativity (fluency, flexibility, originality) and affective domains of creativity (independence, curiosity, diversity, sensitivity, sense of humor, individuality. To analyze data, ANCOVA(Analysis of Covariance)test was conducted, and the results are as belows. Firstly, the group applied in CTFM program was higher than controlled group on the domains of cognitive and affective. Specifically, in the factors of fluency, flexibility and originality among three cognitive domains and factors of individuality.In affective domains of creativity, independence, curiosity, diversity, a sense of humor among the five factors except of sensitivity were higher. Secondly, the result of analyzing the difference between before and after applying CTFM program was that three elements in cognitive domains : fluency, flexibility and originality improved, especially, the fluency was the most improved. Thirdly, the result of analyzing the difference of affective factor between before and after applying CTFM program was that the originality, diversity, a sense of humor and individuality among the 6 elements of affective domain improved, especially the individuality was the most improved.

• Journal of Korean Elementary Science Education
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• v.23 no.4
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• pp.273-278
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• 2004

According to Piaget, children aged 11 are in the middle of concrete operation period and formal operation period. So, it is necessary to adopt the Learning Cycle Model (LCM) which helps students improve their cognitive development. After determining the test for the Science Concept of Matter (SCOM), the experimental group showed higher average than the comparative group in the post-test. In the sound understanding, the experimental group showed higher ratio than the comparative group. And in the ratio of imperfect, wrong understanding and no response, the experimental group was lower than the comparative group. On the questions that were needed the complicated inquiry, many students of both groups still couldn't find the fundamental cause. In forming the scientific conceptualization, there was a meaningful difference (p < .001) after post-test Analysis of Covariance (ANCOVA) with pre-test result. After determining the test for the Test Inquiry Science Process (TISP), the experimental group showed higher average than the comparative group in the post-test. In the category of basic inquiry process which is needed in concrete operation, there was a meaningful difference (p < .05). In the category of unified inquiry process which is needed in formal operation, they showed no meaningful difference (p > .05). Therefore, applying the LCM to the chapter of 'Solution and Dissolving' is more effective on improving the scientific conceptualization and on helping the concrete operation abilities than the teacher centered learning.

• Korean Journal of Childcare and Education
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• v.16 no.5
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• pp.27-45
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• 2020

Objective: The purpose of this study is to develop a music making program that utilizes the characteristics of the picture books medium through the ADDIE model so that teachers can easily apply it to children, and to determine whether it affects children's musical aptitude and music creativity. Methods: The Participants of the study were 42 five-year-old children attending a daycare in Seoul, of which 20 were in the experimental group and 22 in the comparative group. The experimental group participated in a music production program using picture books, and during the same period, the comparison group participated in music activities suggested by the Nuri Course. Using the SPSS 22.0 program, average, standard deviation, independent sampling t-test, and ANCOVA(Analysis of Covariance) were calculated. Results: The music making program using picture books improved children's rhythm and tone which are the sub-items of music aptitude. The music making program enhanced children's music flexibility, music creativity, music logic which are the sub-items of music creativity. Conclusion/Implications: The music making program presented systemic teaching-learning method with which teachers explained the modeling and practiced from simple activities to various activities repeatedly in order to make teachers approach music making more easily. It is recommendable to make the music making program by using I-pad and computers.

• Nutritional Sciences
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• v.6 no.2
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• pp.118-126
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• 2003

To prevent food-borne diseases and ensure food safety, foodservice operators have been implementing the HACCP system in their facilities. Employees' knowledge of food safety can be improved through training and, as a result, their food safety behavior can be positively changed. A nonequivalent pretest and posttest control group model was designed to investigate the effectiveness of HACCP-based training on hospital foodservice employees' food safety knowledge and behavior, and to determine relationships between food safety knowledge and food safety behavior. The subjects used in this study were 84 hospital foodservice employees, assigned either to the intervention group (n=44) or the control group (n=40). Data were analyzed using the Statistical Package for the Social Sciences (SPSS). Descriptive statistics were computed, while the Student's t-test and ANCOVA (Analysis of Covariance) were used to investigate significant differences between groups, and the Pearson correlation was used to determine significant correlations. There were significant gains in both food safety knowledge and behavior, after the HACCP-based training. However, no significant correlation was found between food safety knowledge and food safety behavior. Based on this study we conclude that HACCP-based training is effective in improving both the food safety knowledge and food safety behavior of hospital foodservice employees.