• 제목/요약/키워드: Non-normality

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비정규 공정하에 붓스트랩 EWMA관리도의 수행도 평가 (Evolution of Performance for Bootstrap EWMA Control Chart under Non-normal Process)

  • 이만웅;송서일
    • 산업경영시스템학회지
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    • 제25권2호
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    • pp.50-56
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    • 2002
  • In this study, we establish bootstrap control limits for EWMA chart by applying the bootstrap method, called resampling, which could not demand assumptions about pre-distribution when the process is skewed and/or the normality assumption is doubt. The results obtained in this study are summarized as follows : bootstrap EWMA control chart is developed for applying bootstrap method to EWMA chart, which is more sensitive to small shifts of process. With the purpose of eliminating a skewness of the resampling distribution, the bootstrap control limits are established by using a modified residual, and its performance is analyzed by ARL. It is shown that the bootstrap EWMA control chart developed in this study includes the properties of standard EWMA control chart that is sensitive to a small shift, and detects process in out of control more quickly than standard EWMA chart.

고등학생의 수학 자기조절 학습 요인에 대한 집단별 수준 차이 비교 (Comparison of Differences in Levels per Group on Math Self-Regulated Learning Factors of High School Students)

  • 유기종
    • 한국수학사학회지
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    • 제34권1호
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    • pp.21-37
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    • 2021
  • The purpose of the present study is to compare the differences in levels per group of high school students regarding the self-regulated learning factors for mathematics. For this purpose, a self-regulated learning measurement tool was developed and surveys were conducted. And the statistical analysis was completed using the frequency analysis, Kolmogorov-Smirnov normality test, Mann-Whitney U test and the Kruskal-Wallis H test. As a result, it is found that self-efficacy is of statistically significant differences in self-regulated learning levels regardless of the group classifications but test anxiety does not show statistically significant differences in self-regulated learning levels regardless of the group classifications.

Perceived Risk Factors Affecting Consumers' Online Shopping Behaviour

  • THAM, Kok Wai;DASTANE, Omkar;JOHARI, Zainudin;ISMAIL, Nurlida Binti
    • The Journal of Asian Finance, Economics and Business
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    • 제6권4호
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    • pp.249-260
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    • 2019
  • The study examines the impact of financial risk, convenience risk, non-delivery risk; return policy risk and product risk on online consumer behavior of Malaysian consumers. The research employed a self-administered survey to collect empirical data from 245 Malaysian online shoppers by using convenience sampling. Cronbach alpha was calculated to confirm the reliability of the data and then normality was assessed. Confirmatory Factor Analysis was then conducted to test the model using the goodness-of-fit tests. And finally, structural equation modeling is used to test the hypotheses and draw conclusions. IBM SPSS AMOS version 22.0 was utilized for data analysis. The research indicates that product risk, convenience risk, and return policy risk have a significant and positive impact on online shopping behavior. Financial risk is found to have insignificant and negative effects on consumer behavior. In addition, the non-delivery risk is found to have a significant and negative impact on online shopping behavior. The findings provide a useful model for measuring and managing perceived risk in online shopping which may result in an increase in participation of Malaysian consumers and reduce their cognitive deficiencies in the e-commerce environment. Several managerial implications are discussed along with the scope for future research.

금융 및 특수시계열 모형의 조망 (A recent overview on financial and special time series models)

  • 황선영
    • 응용통계연구
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    • 제29권1호
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    • pp.1-12
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    • 2016
  • 금융시계열은 일반 시계열과는 차별적으로 stylized facts로 불리는 특징을 가지고 있다. 이 특징들은 급첨 성질, 비정규분포, 변동성 집중 및 비대칭성을 포함한다. 이러한 특징들을 설명하기 위해서는 기존의 선형 ARMA 모형에서 벗어난 특수한 모형이 필요하게 되었다. 본 논문은 변동성 모형인 GARCH 형태의 모형을 중심으로 특수 금융시계열 모형들을 소개하고 연관된 통계적 이슈들에 대해 가능한 최근 연구를 중심으로 폭 넓게 조망하고 있다.

Entrenchment Effect and Audit Quality in Family Business of Pakistan

  • TAHIR, Safdar Husain;AKRAM, Sadaf;PERVEEN, Shahida;AHMAD, Gulzar;ULLAH, Muhammad Rizwan
    • The Journal of Asian Finance, Economics and Business
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    • 제7권8호
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    • pp.95-102
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    • 2020
  • The purpose of this study is to test both the alignment theory and entertainment theory on family firms listed on the Pakistan Stock Exchange. To achieve these goals, we collected secondary data from 164 non-financial family firms in various sectors during 2014-18. These family firms are classified into two categories: family control firms and family owned firms. We take the audit fee and the audit quality as dependent variables while family control firms, family-owned firms, and family CEOs as independent variables. In addition, the study uses leverage, profit and export as control variables. To test the effect of the explanatory variables on the output variables, we use two econometric models, Ordinary Least Square and the Probit regression model. In addition, Huber Sandwich test is used to check the non-normality and heteroscedasticity of panel data. Contrary to the alignment effect, the study supports the entrenchment effect and advocates that family-controlled firms as well as family-owned firms are not conscientious regarding the selection of external auditors during their contracts with audit firms. They are less likely to pay high audit fees for good quality audit in Pakistan. Furthermore, the study shows a statistically significant and positive relationship between audit quality and audit fees.

야전 치명고장자료를 이용한 함정전투체계 신뢰성 분석 및 활용 방안 (A Study of Reliability Analysis and Application on Naval Combat System Using Field Critical Failure Data)

  • 김영진;오현승;최봉완
    • 산업경영시스템학회지
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    • 제39권4호
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    • pp.49-59
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    • 2016
  • Naval combat system developed in-country is progressing at an alarming rate since 2000. ROK navy will be achieved all vessels that have combat system in the near future. The importance of System Engineering and Integrated Logistics Support based on reliability analysis is increasing. However, reliability analysis that everyone trusted and recognized is not enough and applied practically for development of Defense Acquisition Program. In particular, Existing Reliability Analysis is focusing on reliability index (Mean Time Between Failure (MTBF) etc.) for policy decision of defense improvement project. Most of the weapon system acquisition process applying in the exponential distribution simply persist unreality due to memoryless property. Critical failures are more important than simple faults to ship's operator. There are no confirmed cases of reliability analysis involved with critical failure that naval ship scheduler and operator concerned sensitively. Therefore, this study is focusing on Mean Time To Critical Failure (MTTCF), reliability on specific time and Operational Readiness Float (ORF) requirements related to critical failure of Patrol Killer Guided missile (PKG) combat system that is beginning of naval combat system developed in-country. Methods of analysis is applied parametric and non-parametric statistical techniques. It is compared to the estimates and proposed applications. The result of study shows that parametric and non-parametric estimators should be applied differently depending on purpose of utilization based on test of normality. For the first time, this study is offering Reliability of ROK Naval combat system to stakeholders involved with defense improvement project. Decision makers of defense improvement project have to active support and effort in this area for improvement of System Engineering.

침수기간이 배추의 생육, 생리적 반응 및 수량에 미치는 영향 (Influence of Waterlogging Period on the Growth, Physiological Responses, and Yield of Kimchi Cabbage)

  • 이상규;이희주;김성겸;최장선;박성태
    • 한국환경과학회지
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    • 제25권4호
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    • pp.535-542
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    • 2016
  • This study was conducted to investigate effects of waterlogging on the growth, physiological responses, and yield of Kimchi cabbage. The growth of Kimchi cabbage with applied optimized air temperature (set to $20^{\circ}C$) was greater than those with high air temperature (set to $30^{\circ}C$) and the growth significantly decreased by severe waterlogging treatment. The net photosynthetic rate of outer leaves on one hour after waterlogging treatment was higher at 72 hours waterlogging treatment in $20^{\circ}C$ and lower at 24 hours of waterlogging treatment in $30^{\circ}C$. The root activity was decreased by the elevation of waterlogging periods in $20^{\circ}C$ treatment and lower by the short of waterlogging periods in $30^{\circ}C$ treatment. The ratio of formality with non-waterlogging treatment was approximately 64% under $20^{\circ}C$ air temperature and that of range was from 16 to 30% under $30^{\circ}C$. The yield under $20^{\circ}C$ showed higher than that under high air temperature. The non-waterlogging treatment in $20^{\circ}C$ had 4,463 kg/10a, which was the greatest among all treatments, while yields of non-waterlogging treatment at $30^{\circ}C$ were significantly low as 1,082 kg/10a. Results suggested that additional drainage work should be needed to overcome waterlogged conditions of open field during heavy rainfall and should be drainage as soon as possible if there are waterlogging.

Новая нормальность в АТР: Пекин между Москвой и Вашингтоном (New Normality in the Asia-Pacific Region: Beijing between Moscow and Washington)

  • Луконин Сергей Александрович;Чже Сун Хун
    • 분석과 대안
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    • 제7권1호
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    • pp.229-258
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    • 2023
  • Для основных ведущих стран Азиатско-Тихоокеанского региона США, Китая и России сложилась ситуация "новой нормальности". Причем для каждой из указанных стран эта "новая нормальность" имеет свои собственные особенности, характеристики и значение. Для США – это обострение военного противостояния с Китаем в Тайваньском проливе. Для Китая – обострение соперничества с Соединенными Штатами до нового уровня и, одновременно, замедление темпов экономического развития с очень высокой вероятностью их дальнейшего снижения. "Новая нормальность" для России – это почти полное свертывание отношений с США, ЕС и их партнёрами и союзниками на фоне специальной военной операции и введенных санкций. Эти нюансы, в дополнение к результатам 20-го съезда КПК, во многом и будут определять основные тенденции в китайско-американских и китайско-российских отношениях. С высокой вероятностью отношения Китая и России не претерпят серьезных изменений на фоне украинского кризиса. Пекин будет стараться сохранять позицию "доброжелательного нейтралитета" по отношению к Москве. В то же время баланс между "доброй волей" и "нейтралитетом" может варьироваться в зависимости от масштабов китайско-российского сотрудничества. Например, в экономической сфере китайские компании будут лимитировать сотрудничество с российскими партнерами, опасаясь западных вторичных санкций. Однако, в целом, Россия сохранит свое значение для Китая как сильнейший антиамериканский полюс. В отношениях с США Китай продолжит твердо отстаивать свои интересы, в то же время, не исключая нормализации отношений с Вашингтоном в определенных областях сотрудничества: стратегическая стабильность, нетрадиционные угрозы, экология и т.д. В целом решения 20-го съезда КПК не позволяют говорить ни за, ни против идеи о готовности Китая возобновить диалог с США в период после конгресса. Китайско-американские отношения, как отмечалось выше, имеют свою собственную логику и, вероятно, продолжат развиваться в ее рамках. Впрочем, как и китайско-российские отношения. В рамках этой логики Пекин, похоже, продолжает балансировать между двумя векторами своей внешней политики. С одной стороны – это развитие двустороннего сотрудничества с Россией с целью укрепления собственных переговорных позиций в противостоянии с Вашингтоном: военное сотрудничество с акцентом на совместные учения, политическое сотрудничество, основанное на антиамериканизме, экономическое сотрудничество с оглядкой на риски вторичных санкций. С другой стороны, для Китая неприемлемо, во-первых, нарушение территориальной целостности Украины, во-вторых, прямое военное столкновение с США и, в-третьих, дальнейшее обострение отношений с Вашингтоном по фактору китайской дружбы с Россией.

A Study on the Effectiveness of Face-to-face Physical Therapy and Non-face-to-face Physical Therapy in Individuals With Rounded Shoulder

  • Young-ji Cho;Min-je Kim;Cho-won Park;Ye-bin Cho;In-A Heo;Su-jin Kim
    • 한국전문물리치료학회지
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    • 제30권1호
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    • pp.50-58
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    • 2023
  • Background: This study was carried out to determine whether non-face-to-face physical therapy would have similar exercise effects to face-to-face physical therapy. Hence, we developed an approach for patients, unable to visit hospitals due to circumstances such as the COVID-19 pandemic, to conduct physical therapy comfortably at home. Objects: This study aimed to compare the effects of a face-to-face and a non-face-to-face physical therapy treatment on improving a rounded shoulder posture. Methods: The participants with rounded shoulders were randomly divided into a face-toface group (n = 15) and a non-face-to-face group (n = 15), and each group performed exercises for four weeks. The exercise program consisted of the bare hands exercise, Thera-Band exercise, and foam roller exercise. The participants in the face-to-face group came to a designated place to perform their exercises, and those in the non-face-to-face group performed the exercises at their own home using Google Meet (Google). Acromial height, total scapular distance (TSD), shoulder pain and dysfunction index (SPADI), and pectoralis minor thickness were measured. Data analysis was performed using the R Statistical Software (R Core Team), and a normality test was performed using the Shapiro-Wilk test. Results: There were no significant differences between the face-to-face and the non-face-toface groups (p > 0.05). When comparing the differences before and after the exercises, both the face-to-face and the non-face-to-face groups showed significant differences in acromial height, SPADI, and pectoralis minor thickness (p < 0.05), and both groups showed no significant difference in TSD before and after the exercises (p > 0.05). Conclusion: The results of this study support the results of previous studies reporting that shoulder stabilization exercise and pectoralis minor stretching training improves round shoulders. In addition, this study revealed that both the face-to-face and the non-face-to-face physical therapy treatments had therapeutic effects.

Practical statistics in pain research

  • Kim, Tae Kyun
    • The Korean Journal of Pain
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    • 제30권4호
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    • pp.243-249
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    • 2017
  • Pain is subjective, while statistics related to pain research are objective. This review was written to help researchers involved in pain research make statistical decisions. The main issues are related with the level of scales that are often used in pain research, the choice of statistical methods between parametric or nonparametric statistics, and problems which arise from repeated measurements. In the field of pain research, parametric statistics used to be applied in an erroneous way. This is closely related with the scales of data and repeated measurements. The level of scales includes nominal, ordinal, interval, and ratio scales. The level of scales affects the choice of statistics between parametric or non-parametric methods. In the field of pain research, the most frequently used pain assessment scale is the ordinal scale, which would include the visual analogue scale (VAS). There used to be another view, however, which considered the VAS to be an interval or ratio scale, so that the usage of parametric statistics would be accepted practically in some cases. Repeated measurements of the same subjects always complicates statistics. It means that measurements inevitably have correlations between each other, and would preclude the application of one-way ANOVA in which independence between the measurements is necessary. Repeated measures of ANOVA (RMANOVA), however, would permit the comparison between the correlated measurements as long as the condition of sphericity assumption is satisfied. Conclusively, parametric statistical methods should be used only when the assumptions of parametric statistics, such as normality and sphericity, are established.