• Journal of the Korean Institute of Intelligent Systems
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• v.21 no.1
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• pp.25-28
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• 2011

In this paper, we study some properties of condition for fuzzy data, agrement index by ratio of area and the uniformly most powerful fuzzy test of hypothesis. Also, we suggest a confidence bound for uniformly most powerful fuzzy test. For illustration, we take the most powerful critical fuzzy region from exponential distribution by likelihood ratio and test the hypothesis of ${\chi}^2$-distribution by agreement index.

• Communications for Statistical Applications and Methods
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• v.18 no.3
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• pp.287-294
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• 2011

Peer assessment is an educational valuation system that involves studying with a colleague and granting value to the progress made by the colleague. Although this method has many merits, there is also a drawback pertaining to calculating the mean of the scores that were granted to the levels of contribution. However, this has been improved upon by a diversified study. However, the concept of the chi-square test and p-value used in the preceding study is not easy individuals engaged in the industrial engineering field or education when using peer assessment. This study uses simple statistics like standard deviation, in addition to, investigating the availability of a suggested method as well as examples of utility and application. This study can contribute to increase the convenience of users through the use of convenience analysis and with this method.

• The Mathematical Education
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• v.62 no.1
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• pp.151-173
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• 2023

In this study, we explored factors that affect high school student's affective attitude on mathematics with respect to the school mathematics instructoin, school mathematics assessment, mathematics textbook, private mathematics education, college entrance and career, and social atmosphere. Considering students' grade, major, academic level, gender, and school location, 1,029 high school students participated in the survey. To analyze the survey results, descriptive statistics, t-test, ANOVA, and chi-square test were conducted using SPSS ver 29.0. Results are as follows. First, generally, college entrance and career and school mathematics instruction affected students' affective attitude on mathematics. Second, according to student's academic level and gender, there was a statistically significant difference in the factors affecting the affective attitude on mathematics. Third, according to students' background, there was a statistically significant difference in students' responses to sub-categories of each factor. We suggested that to improve student's affective attitude on mathematics, diversity of the school mathematics instruction, improvement of the mathematics textbook, student's appropriate participation in the private mathematics education, improvement of student's perception of the utilization of the mathematics in the future and the importance of the mathemaitcs in the society, and parents' emotional support are needed.

• Journal of Korean Society of Transportation
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• v.28 no.1
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• pp.51-61
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• 2010

The main objective of this paper is to analyze change of travel patterns according to public transportation reform. The paper uses data collected from Gyeongsan City. So far few researches, especially using before-and-after individual travel survey, have been conducted on analyzing effects of public transportation reform. For this research, some descriptive statistical analyses and statistical hypotheses tests were conducted. Furthermore, some empirical logit models were estimated for analyzing the individual effects of the public transportation reform. Finally, some important foundings, policy implications, and limitations of this research are discussed.

• Journal of the Korean Data and Information Science Society
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• v.27 no.2
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• pp.373-380
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• 2016

Even though Likert type data is ordinal scale, many researchers who regard Likert type data as interval scale adapt as parametric methods. In this research, simulations have been used to find out a proper analysis of Likert type data. The locations and response distributions of five point Likert type data samples having diverse distribution have been evaluated. In estimating samples' locations, we considered parametric method and non-parametric method, which are t-test and Mann-Whitney test respectively. In addition, to test response distribution, we employed Chi-squared test and Kolmogorov-Smirnov test. In this study, we assessed the performance of the four aforementioned methods by comparing Type I error ratio and statistical power.

• Journal of the Korean Data Analysis Society
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• v.20 no.6
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• pp.2813-2827
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• 2018

Progressive censoring schemes have become quite popular in reliability study. Under progressive censored data, however, some units can be failed between two points of observation with exact times of failure of these units unobserved. For example, loss may arise in life-testing experiments when the failure times of some units were not observed due to mechanical or experimental difficulties. Therefore, multiply progressive censoring scheme was introduced. So, we derives a maximum likelihood estimator of the parameter of exponential distribution. And we introduced the goodness-of-fit test statistics using order statistic and Lorenz curve. We carried out Monte Carlo simulation to compare the proposed test statistics. In addition, real data set have been analysed. In Weibull and chi-squared distributions, the test statistics using Lorenz curve are more powerful than test statistics using order statistics.

• Industry Promotion Research
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• v.5 no.1
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• pp.13-20
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• 2020

This study is about consumer preference of plastic toilets that can provide automatic supply of recycled water. First, the preference for plastic toilet seat design by gender and age group was preferred for gender type C and G for the sex. As the result of the chi-square test, the significance probability is .044 and the significance is P <.0 5. I could confirm that. Age, teens, 40 s, and 50 s or older prefer type C, 20 s and 30 s, but B type is not statistically significant. Second, the differences among the groups of preference for appearance design criteria according to general characteristics were all stable (stable appearance) in gender, age, region, education, and salary, but the chi-square test showed that they were not statistically significant. There was no difference between them. This study has implications for improving competitiveness and productivity by reducing the main production cost by commercializing toilets made of plastic materials.

• The Korean Journal of Applied Statistics
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• v.29 no.1
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• pp.61-73
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• 2016

We consider the wild bootstrap Ljung-Box (LB) test for autocorrelation in residuals of fitted multivariate time series models. The asymptotic chi-square distribution under the IID assumption is traditionally used for the LB test; however, size distortion tends to occur in the usage of the LB test, due to the conditional heteroskedasticity of financial time series. In order to overcome such defects, we propose the wild bootstrap LB test for autocorrelation in residuals of fitted vector autoregressive and error correction models. The simulation study and real data analysis are conducted for finite sample performance.

• Journal of the Korean Data and Information Science Society
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• v.24 no.1
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• pp.73-83
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• 2013

Among class quantitative tests for the credit rating systems, the credit rating tests for calibration are to test the class homogeneous differences between observed and predicted probabilities. For one time period, binomial test and chi-square test are included, and normal test and extended traffic lights test are also contained for several time peroids. In this work, we consider real data in which there exists correlation among variables, so that these test methods could be applied to the credit rating systems as well as various kinds of the class data such as BWT data and FSI data.

• The Korean Journal of Applied Statistics
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• v.30 no.1
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• pp.147-157
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• 2017

The test of transition probabilities in panel Markov chains are introduced. We deal with the hypotheses whether panel Markov chains have the same transition probabilities or not for all times. We suggest a LR test statistic for the test and its limit distribution is derived. We perform a simulation study to examine the limit distribution of test statistics when the number of the individuals are large.