• Title/Summary/Keyword: Test of Normality

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Power Comparison of EGLS Test Statistic for Fixed Effects with Arbitrary Distributions

  • Lee, Jang-Taek
    • Communications for Statistical Applications and Methods
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    • v.10 no.1
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    • pp.11-18
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    • 2003
  • Quite often normality assumptions are not satisfied in practical applications. In this paper, an estimated generalized least squares(EGLS) analysis are considered in two way mixed linear models with arbitrary types of distributions for random effects. We investigate the power performance of EGLS analysis based on Henderson's method III, ML, REML and MINQUE(1). The power performances depend on the imbalance of design, on the actual values of ratio of variance components, and on the skewness and kurtosis parameters of the underlying distributions slightly. Results of our limited simulation study suggest that the EGLS F-statistics using four estimators and arbitrary distributions produce similar type I error rates and power performance.

Modified Mass-Preserving Sample Entropy

  • Kim, Chul-Eung;Park, Sang-Un
    • Communications for Statistical Applications and Methods
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    • v.9 no.1
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    • pp.13-19
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    • 2002
  • In nonparametric entropy estimation, both mass and mean-preserving maximum entropy distribution (Theil, 1980) and the underlying distribution of the sample entropy (Vasicek, 1976), the most widely used entropy estimator, consist of nb mass-preserving densities based on disjoint Intervals of the simple averages of two adjacent order statistics. In this paper, we notice that those nonparametric density functions do not actually keep the mass-preserving constraint, and propose a modified sample entropy by considering the generalized 0-statistics (Kaigh and Driscoll, 1987) in averaging two adjacent order statistics. We consider the proposed estimator in a goodness of fit test for normality and compare its performance with that of the sample entropy.

Design of Air Vehicle Test Equipment for Inspecting On-board Equipment in UAV (무인항공기 탑재장비 점검을 위한 통합 점검 장치 설계)

  • Go, Eun-kyoung;Kwon, Sang-Eun;Song, Yong-Ha
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.25 no.1
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    • pp.108-114
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    • 2021
  • AVTE(Air Vehicle Test Equipment) is a device to check status of on-board aircraft equipment before and after flight for performing successful UAV(Unmanned Aerial Vehicle) missions. This paper describes software design and test sequence of the AVTE for enabling easy-manual check by the operator and convenient automatic check of on-board electric equipment respectively. The proposed AVTE inspects BIT(Built-In Test) results of on-board LRUs(Line Replacement Units) including avionics and sensor sub-system devices. Also, it monitors all the LRU status and check the normality of aircraft equipment by means of setting specific values of the LRUs and confirming the expected test results. The AVTE prints the test results as a form of report to easily check the normal conditions of the aircraft equipment and operates automatically without operator interaction, thus being thought to effectively reduce workload of the operator.

A Study on the Effects of Ethical Dilemma Discussion Program for University Students (대학생의 윤리적 딜레마 토의 프로그램 효과에 관한 연구)

  • Yang, Hyun-Joo;Park, Mee-Ra;Je, Nam-Joo
    • Journal of Digital Convergence
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    • v.17 no.9
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    • pp.291-299
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    • 2019
  • This study is a nonequivalent control group pretest-posttest designed to understand the effect of ethical dilemma discussion program on human rights sensitivity and ethical values of university students. By providing ethical dilemma discussion program to university students in C university, G-do, the effectiveness was verified. Analyzed using IBM SPSS 24.0. The normality of the variables was verified by Shapiro-Wilk test. Homogeneity was verified using real number and percentage, Fisher's exact probability test and independent t-test. The program's effect was verified using paired t-test. The results of this study are as follows: after the ethical dilemma discussion program, the experimental group's human rights sensitivity(t=-2.32, p=.025), and ethical value(t=-2.43, p=.020) were higher than the control group. Therefore, the ethical dilemma discussion program of this study helped improve the human rights susceptibility and ethical values of the subjects. Further research is needed to verify the effects of ethics education on diverse groups.

The Effects of Trust and Perceived Risk on Attitude and Purchase Intension in Internet Shopping Malls (인터넷 쇼핑몰에서 신뢰와 지각된 위험이 태도 및 구매의도에 미치는 영향)

  • Chang, Myung-Hee
    • The Journal of Information Systems
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    • v.14 no.1
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    • pp.227-249
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    • 2005
  • In this research, four antecedents of trust ad the effect of trust and perceived risk on attitude and purchase intension in internet shopping malls is investigated. In survey, data were collected from 286 male and female internet shopping mall users, and then covariance structure modeling through Amos was used to test the 10 hypotheses. The survey results as follow: First, this research shows that institution base structural assurance and situational normality and knowledge-based familiarity are important antecedents on trust in internet shopping malls. Second, trust affected attitude and purchase intension. Third, it has a negative relationship between trust and perceived risk. But perceived risk does not influence attitude and purchase intension. This study contribute to understanding on the role of trust and perceived risk in internet shopping malls.

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Comparison and Evaluation of Performance for Standard Control Limits and Bootstrap Percentile Control Limits in $\bar{x}$ Control Chart ($\bar{x}$ 관리도의 표준관리한계와 부트스트랩 백분률 관리한계의 수행도 비교평가)

  • 송서일;이만웅
    • Journal of Korean Society of Industrial and Systems Engineering
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    • v.22 no.52
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    • pp.347-354
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    • 1999
  • Statistical Process Control(SPC) which uses control charts is widely used to inspect and improve manufacturing process as a effective method. A parametric method is the most common in statistical process control. Shewhart chart was made under the assumption that measurements are independent and normal distribution. In practice, this assumption is often excluded, for example, in case of (equation omitted) chart, when the subgroup sample is small or correlation, it happens that measured data have bias or rejection of the normality test. A bootstrap method can be used in such a situation, which is calculated by resampling procedure without pre-distribution assumption. In this study, applying bootstrap percentile method to (equation omitted) chart, it is compared and evaluated standard process control limit with bootstrap percentile control limit. Also, under the normal and non-normal distributions, where parameter is 0.5, using computer simulation, it is compared standard parametric with bootstrap method which is used to decide process control limits in process quality.

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Assessment Criteria and Capability Scores for Upper Extremity Functions from Inclusive Design Perspectives

  • Kim, Taesun
    • Science of Emotion and Sensibility
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    • v.19 no.2
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    • pp.89-100
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    • 2016
  • Inclusive design is increasingly gaining attention, as some people find using products difficult after becoming physically impaired, despite daily use. However, making inclusive products is a challenge for designers or companies, as a lack of knowledge and tools stems their low involvement in it. Developing inclusive design tools is thus needed. This study developed criteria to assess upper extremity capabilities corresponding to specific daily activities. A questionnaire survey was conducted among 58 physiatrists and orthopedists. Non-parametric statistics were employed and medians were adopted as representative scores in the assessment criteria based on normality and reliability test results, non-normal data, and strong reliability of respondents in ranking. Consequently, an assessment tool was developed with 14 criteria (divided into range of motion and strength) and capability scores between 0 and 100, which discerned the moderately impaired from the severely disabled and fully capable. Since the doctors agreed to adopt the criteria but assign numeric values, especially for mild impairments, their capability assessment perception was likely influenced by dichotomy. To compensate for these deficits, qualitative or ergonomic approaches are considered simultaneously.

Permutation Predictor Tests in Linear Regression

  • Ryu, Hye Min;Woo, Min Ah;Lee, Kyungjin;Yoo, Jae Keun
    • Communications for Statistical Applications and Methods
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    • v.20 no.2
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    • pp.147-155
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    • 2013
  • To determine whether each coefficient is equal to zero or not, usual $t$-tests are a popular choice (among others) in linear regression to practitioners because all statistical packages provide the statistics and their corresponding $p$-values. Under smaller samples (especially with non-normal errors) the tests often fail to correctly detect statistical significance. We propose a permutation approach by adopting a sufficient dimension reduction methodology to overcome this deficit. Numerical studies confirm that the proposed method has potential advantages over the t-tests. In addition, data analysis is also presented.

Does Access to Finance Eradicate Poverty? A Case Study of Mudra Beneficiaries

  • SALGOTRA, Ajay Kumar;KANDARI, Prashant;BAHUGUNA, Uma
    • The Journal of Asian Finance, Economics and Business
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    • v.8 no.1
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    • pp.637-646
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    • 2021
  • The main objective of this study was to investigate the impact of access to finance on the different dimensions of poverty. To achieve the objectives of the study, the participants/beneficiaries of the Mudra scheme were included and sample of target respondents was extracted through multistage random sampling technique. The sample for the study was taken from the Union Territory of Jammu and Kashmir of India. The study further utilized secondary data from the government official websites and lead banks. A paired t-test was applied to test the impact of access to finance across the various dimensions of poverty by constructing the Multidimensional Poverty Index(MPI), after checking the normality of the data. MPI incorporates dimensions such as education, health, and standard of living.The finding of the study revealed that dimensions of poverty responded positively to access to finance. The study shows that larger access to finance has helped in reducing the multidimensional poverty by having moderate, but positive impact on the standard of living, health, and education, thereby improving the lives of the poor. The present study identified that the level of impact of access to finance is moderate and further explains its importance for policy implications.

Experimental Study of Error Canceling on the Piercing Depth of Concrete by Single Shot and Barrage of Small Caliber Bullets (소구경 탄자 연발사격 시 콘크리트 관입깊이 오차 상쇄 실험 연구)

  • Lim, Chaeyeon;Kim, Kuk-Joog;Park, Young-Jun
    • Proceedings of the Korean Institute of Building Construction Conference
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    • 2019.11a
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    • pp.35-36
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    • 2019
  • Major influence factors for piercing depth of concrete against small caliber bullet are target's property such as compression strength of concrete and bullet's property such as the velocity and weight of it. In particular about the bullet's property, velocity and incidence angle could be controlled by specific position or distance between targets and shooter, but the angle of yaw of bullet dose not. Because the the angle of yaw of bullet causes lower piercing force of bullet, some errors on piercing depth of concrete could be appeared by live fire test for the evaluation of protective performance. Therefore, we have checked the error canceling effect on the piercing depth of concrete by single shot and barrage of small caiber bullets. As a result, we identified that the error of piercing depth by the angle of yaw of bullet could be cancelled by barrage.

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