• Communications for Statistical Applications and Methods
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• v.31 no.1
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• pp.1-35
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• 2024

The assumption of homoscedasticity is one of the most crucial assumptions for many parametric tests used in the biological sciences. The aim of this paper is to compare the empirical probability of type I error and the power of ten parametric and two non-parametric tests for homoscedasticity with simulations under different types of distributions, number of groups, number of samples per group, variance ratio and significance levels, as well as through empirical data from an agricultural experiment. According to the findings of the simulation study, when there is no violation of the assumption of normality and the groups have equal variances and equal number of samples, the Bhandary-Dai, Cochran's C, Hartley's Fmax, Levene (trimmed mean) and Bartlett tests are considered robust. The Levene (absolute and square deviations) tests show a high probability of type I error in a small number of samples, which increases as the number of groups rises. When data groups display a nonnormal distribution, researchers should utilize the Levene (trimmed mean), O'Brien and Brown-Forsythe tests. On the other hand, if the assumption of normality is not violated but diagnostic plots indicate unequal variances between groups, researchers are advised to use the Bartlett, Z-variance, Bhandary-Dai and Levene (trimmed mean) tests. Assessing the tests being considered, the test that stands out as the most well-rounded choice is the Levene's test (trimmed mean), which provides satisfactory type I error control and relatively high power. According to the findings of the study and for the scenarios considered, the two non-parametric tests are not recommended. In conclusion, it is suggested to initially check for normality and consider the number of samples per group before choosing the most appropriate test for homoscedasticity.

• Asia pacific journal of information systems
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• v.15 no.4
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• pp.61-87
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• 2005

This paper has two primary objectives: (1) to propose a comprehensive theoretical model that incorporates valuable insights from two complementary streams of research, and (2) to empirically test the model that explain the task-media fit and satisfaction of customer contact center users. The comprehensive model was tested using LISREL analysis on the sample of 232 users who have experience with the customer contact center. The model was supported in customer contact center context, accounting for 29% of the variance in the task-media fit, 53% of the variance in the perceived ease of use, 61% of the variance in the perceived usefulness, and 52% of the variance in the user satisfaction. The results showed that the task-media fit, the perceived ease of use, and the perceived usefulness play a significant role in influencing the user satisfaction of the customer contact center. In addition, task analyzability, media richness, media interactivity, and self-efficacy were found to influence the task-media fit. The paper concludes with discussions and implications for researchers and practitioners.

• The Journal of Korean Society for School & Community Health Education
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• v.15 no.3
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• pp.105-125
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• 2014

Background: The purpose of this study was to evaluate reliability and validity of a 27-item Korean Version of the Impact of Weight on Quality of Life in adolescents ($IWQOL-Kids^{(C)}$: Korean Version). Methods: This instrument was administered to 872 adolescents (mean z-BMI: 2.61, mean $age{\pm}SD$: $13.9{\pm}1.2$, male: 51.9%). Reliability was tested by internal consistency method and item analysis, validity test was performed by index of content validity, exploratory factor analysis, confirmatory factor analysis and concurrent validity. Sensitivity was tested by ANOVA and t-test. Analyses were performed using SPSS and Amos 18.0. Results: By an exploratory factor analysis, 4 factors were extracted; 'Body esteem' consisted of 9 items with 35.9% of variance (social life: 6 items, 10.23%, physical comfort: 6 items, 8.21%, family relations: 6 items, 7.0%). Four factors explained 61.34% of total variance. Internal consistency coefficients ranged from .766 to .929 for scales on 27 items and equal to .920 for total score for both the 26-item and 27-item tools. A confirmatory factor analysis was conducted for the convergent validity and discriminant validity. The standardized factor loadings to test the convergent validity showed more than .5(C.R<1.965) on all paths after deletion of item PC1 (avoid stairs). The average variances extracted were more than .50 and the construct reliabilities were more than .70. The average variances extracted were stronger than the squares of correlation coefficient of inter-latent variables. Conclusions: These results support that the $IWQOL-Kids^{(C)}$: Korean Version with a 26-item is a reliable and valid tool in Korean obese adolescents.

• Journal of the Korean Society of Clothing and Textiles
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• v.14 no.4 s.36
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• pp.245-251
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• 1990

The purposes of the study were to efplain the independent influences of Asthetic Expression and Fashion on aesthetic evaluation in the clothing, to examine which in more important aesthetic components such as line/style, color, textile and detail in aesthetic evaluation in the clothing. Data were obtained from 221 female students living in Seoul area by eight photo-graphs of clothed bodies and a questionnaire. The data were analysied by Pearson's correlation, Analysis of valiables, scheffe-test and Regression analysis. The results of the study were as follows; 1. In the aesthetic evaluation of clothing, the $59.30\%$ of the total variance was explained by Aesthetic Expression, the $20.91\%$ of the total variance was explained by Fashion and $59.68\%$ of the total variance were explained by Aesthetic Expression and Fashion. More important variable of aesthetic evaluation was found to be an Aesthetic Expression. 2. Among aesthetic components such as line/style, color, textile and detail in aesthetic evaluation of the clothing, such general aspects as color and line/style were perceived at first and then specific ones like textile and detail.

• Fashion & Textile Research Journal
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• v.4 no.1
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• pp.40-46
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• 2002

The purpose of this study was to classify the clothing purchasing behavior of department store credit card users according to fashion lifestyle. The questionnaire was administrated to 346 female department store credit card users aged over 20 living in Daegu, Frequency factor analysis, cluster analysis, one-way Analysis of Variance (ANA), MANOVA, Scheffe test, ${\chi}^2$-test and t-test were used for satistical analysis. The consumers' lifestyle was classified by fashion oriented, practical and self conspicuous. The results showed that the credit card users' clothing purchasing behavior was different according to the fashion lifestyle. The self conspicuous group showed the highest score in impulse buying.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.19 no.6
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• pp.9-16
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• 2020

This study aims to assess the effects of specimen thickness (ST) on fatigue crack growth in the early stages of crack propagation and near failure in magnesium alloys. The analysis of variance (ANOVA) method was adopted because fatigue crack propagation in magnesium alloys exhibits statistical behavior. The equality of variance test and residual diagnostics were performed on the grown cracks to confirm the validity of ANOVA by verifying the normal distribution and mutual independence of the residuals and their homoscedasticity. ANOVA confirmed that ST heavily impacts crack growth; i.e., when ST is smaller, cracks grow faster in the early crack propagation stage and break more quickly before the formation of larger cracks. We found that ST significantly affects fatigue crack growth in the early crack propagation stage and near the failure stage in magnesium alloys. The regression model was also used to predict crack formation near the failure stage.

• Journal of Families and Better Life
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• v.27 no.6
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• pp.95-109
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• 2009

This study focused on the development of a scale to measure the ability of consumers to use credit cards. The purposes of this study were to develop a tool which would be able to measure consumer knowledge, consumer skills and consumer attitudes. Data were collected from 313 credit card using consumers and were analyzed by employing a goodness of fit test, principal component analysis & confirmatory factor analysis(Amos 5.0), multiple regression. The results from this study were as follows: 1) Six factors of consumer knowledge(16-items) were identified: damage salvation; credit delinquency; personal credit information; credit provision period; credit & credit card issuance; credit delinquent striking out a record & credit rating. The total variance was 55.86%. 2) Three factors of consumer skills(17-items) were identified: credit delinquency & over-consumption; credit card management; and loss & damage salvation. The total variance was 62.90%. 3) Three factors of consumer attitudes(16-items) were identified: credit delinquency & credit; credit card issuance & use; and credit card management. The total variance was 58.75%.

• Korean Journal of Child Studies
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• v.25 no.6
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• pp.371-383
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• 2004

In this study, 197 4- to 6- year-old Korean children wereindividually tested with Concepts about Print(CAP Clay, 2000), the Picture Vocabulary Test(Kim, Jang, Lim & Bak, 1996), Korean-Wechsler Preschool and Primary Scale of Intelligence : Verbal Test (K-WPPSI), and the Basic Academy Skills Assessment : Reading(Kim, 2000). Data were analyzed by Pearson-correlation, analysis of variance, and factor analysis. There were significant differences of CAP mean scores by age. Within the subcategories of CAP, Book Orientation Concepts and Print-convention were acquired earlier than other subcategories, followed by Print-direction, Print-order and Advanced Print Concepts in that order. The scores of CAP were positively correlated with the Picture Vocabulary Test, the K-WPPSI verbal test and the reading test.

• Journal of Korean Public Health Nursing
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• v.35 no.3
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• pp.343-355
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• 2021

Purpose: This study aimed to identify the effects of nursing students' ethical awareness, ethical decision-making and attitude toward performance on intention about performance of infection control guidelines in pandemic infectious diseases. Methods: The survey was performed on 163 nursing students in three universities. Data were collected using a structured questionnaires and analyzed with t-test, analysis of variance (ANOVA), Pearson's correlation and multiple regression analysis. Results: Perceived health status, ethical awareness and attitude toward performance of infection control guidelines about major commitment were significant predictive variables. These variables accounted for 48.1% of the variance in major commitment. Conclusion: The findings indicate the necessity of developing educational programs to enhance nursing students's ethical awareness, and increase performance of control guidelines to prepare for the pandemic infectious diseases.

• Journal of the Korean Data and Information Science Society
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• v.20 no.4
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• pp.661-672
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• 2009

This study was conducted to investigate whether mat exercise and field exercise have effectiveness on the balance and gait in older adults. Thirty subjects were participated in this study. And they were all randomly divided into mat exercise and field exercise group. To evaluate the effects of mat and field exercise, subjects were evaluated by using One Leg Stand test which was static balance test, and Berg Balance test which was dynamic balance test. Finally Gait pattern was assessed by using 3-dimensional gait analysis system. The assessment parameters were evaluated before, after 3 weeks, and after 6 weeks treatments. And we received a consent form from all subjects. The results of repeated measures analysis of variance showed that One Leg Stand, Berg Balance, Stride length, Cadence, Velocity were significantly increased after than before exercise in both groups. So we conclude that therapeutic exercise that is mat and field exercise has effectiveness on the balance and gait in older adults.