• Title/Summary/Keyword: Hypothesis testing

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A Study on the Performance of the M&A Firm in KOSDAQ (코스닥시장 M&A기업의 성과에 관한 연구)

  • Kim, Kyung-Sik
    • Journal of the Korea Society of Computer and Information
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    • v.12 no.1 s.45
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    • pp.219-229
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    • 2007
  • The results of the research in M&A firms in the KOSDAQ market are as follows. First, the effect of the M&A disclosure at the time of disclosure was that the positive (+) cumulative abnormal return (CAR) can be interpreted as an increase in the value of the firm; however, in the long run, firms which used the KOSDAQ index and the control firm, which did not use the index were found to have conflicting results. Second, the findings show that the rise in value of general firms resulting from a M&A were higher that those of venture firms. Third, in testing the performance extrapolation hypothesis, it was shown that the performance of "value" firms (firms with a high B/M ratio but poor performance in the past) was better after a M&A than those of the "glamour" firms and that the performance extrapolation hypothesis was substantiated. Fourth, it can be construed that a size effect in a merger exists. The CAR of the small firms surpasses those of large firms. Fifth, in verifying operating performance, most variables showed a positive (+) value at the time of M&A but showed a negative (-) value after a M&A. These results show that because on the Korean KOSDAQ market, M&A are approached from a financial rather than an economic aspect, it can be inferred that it lowers the firms value.

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Power Efficient Cell Searching Algorithm to Support Mobility in Portable Digital Broadcasting Networks (휴대용 디지털 방송망에서의 이동성지원을 위한 전력 효율적인 셀 탐색 기법)

  • Park, Hyung-Kun
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.11 no.8
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    • pp.1574-1581
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    • 2007
  • DVB-H (Digital Video Broadcasting for Handhold) is a new standard, currently being developed for a portable digital broadcasting, which enhance the multimedia broadcasting service in the Euroapean standard DVB-T (DVB-Terrestrial). Seamless mobility and power saving are essential requirements in the DVB-H system. To support seamless mobility, DVB-H system should provides seamless handover for mobile stations in the MFN (multi frequency network). For seamless handover, the receiver should monitor neighboring cells and it increases the power consumption. And so, power efficient sell searching algorithm for seamless handover is required. In this paper, we propose hypothesis feeling based handover algorithm to enhance the power efficiency by using the fast cell searching, and analyze the performance of handover schemes through the numerical evaluation and simulation.

Effective Test and Evaluation Approaches for Reliable Defense Systems Development examined through Domestic Defense Cases (국내 사례로 살펴보는 국방체계 개발의 신뢰성을 높이기 위한 시험평가 방안)

  • Seo, Kyung-Min;Lee, Chan Young;Bang, Kyoung Woon;Lee, Dong Chul;Choi, Woo Young;Kim, Tag Gon
    • Journal of the Society of Naval Architects of Korea
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    • v.53 no.2
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    • pp.127-134
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    • 2016
  • This paper presents practical issues for test and evaluation(T&E) methods to develop defense systems. Our argument is motivated by several domestic defense cases and the cases lead us to discuss two main factors for reliable defense systems development: 1) statistical approaches and 2) technical schemes. Specifically, statistical approaches enable to provide credible interpretations about T&E results in the decision-making process. With practical T&E results of the “Red Shark” torpedo, we performed statistical hypothesis tests and suggest a minimum sample size to accept the hypothesis. Next, technical schemes have more direct effects on improving reliability of developed defense systems and we shortly introduce tools development for systems verification that is required to integrate several sub-systems, e.g., combat, sensor, weapon, and communication systems, within a defense system. We additionally summary some domain cases using modeling and simulation techniques for successful T&E. In closing, we expect that the paper shows empirical investigation and lessons learned with these two practical issues, which provides a guide those who desire to make decisions about reliable defense systems development.

The Effect of Authentic Leadership on Creativity: the Multiple Mediating Effection of Psychological Safety and Cooperation Behavior (진성리더십이 창의성에 미치는 영향: 심리적 안전과 협력행동의 다중매개효과)

  • Choi, Woo-Su;Oh, Sang-Jin
    • The Journal of the Korea Contents Association
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    • v.21 no.1
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    • pp.485-497
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    • 2021
  • The purpose of this study is to demonstrate the effects of authentic leadership on creativity, psychological safety, and the mediating effects of cooperative behavior in order to enhance the creativity of personnel as a means of innovation in enterprises. The hypothesis was established based on the theory and prior study of authentic leadership, creativity, psychological safety, cooperation behavior. The data collected from 353 employees of domestic enterprises were verified for reliability and validity through CFA, SPSS 25, and AMOS 25. Macro Process 3.0 was used for hypothesis testing. Verification of the hypothesis of the study model showed that authentic leadership had a significant positive effect on psychological safety, cooperation behavior and creativity, and that the mediating effect of psychological safety and cooperation behavior was also significant. The significance of this study can be found in the fact that the impact of authentic leadership has been verified based on motivation among the CMC (Componential Model of Creativity) and that it has suggested that creativity of an organization's personnel may be enhanced by changing organizational culture through leadership.

A Study on the Effect of Storytelling Marketing on Brand Image and Brand Attitude

  • Kim, Hye-Jin;Park, So-Yeon;Park, Hye-Yoon
    • The Journal of Economics, Marketing and Management
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    • v.6 no.4
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    • pp.1-16
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    • 2018
  • Purpose - This study will investigate and identify the relationship between brand image, brand attitude and intent to purchase based on subjects that have remembered or watched more than one storytelling marketing ad related to airlines. The purpose of the project is to secure market competitiveness by presenting the basis for and use of the marketing strategy using storytelling, which can capture the goodwill of the aerospace competition market in the future. Research, design, data, and methodology - Prior to the research model and hypothesis testing phase, a verification factor analysis was conducted to assess internal consistency among each measurement item and to ensure reliability and validity of the measurement tool. Further, the organization was assessed for validity by calculating the mean variance estimation (AVE) and the construction concept reliability (CCR) through a positive factor analysis. Hypothesis verification was analyzed through a structural equation model, and each concept set in the hypothesis was entered as a potential variable, and each measurement item was entered as an observation variable. Results - Airline's storytelling marketing has a significant impact on the brand image and two emotional and cognitive responses have been shown to influence the brand image. In addition, airline storytelling marketing has a significant impact on brand attitudes and airline storytelling marketing derived from factor analysis has shown two emotional and cognitive responses to brand attitudes. Conclusions - The parts derived based on the research results show that storytelling marketing has a strong influence on the airline's brand image and attitude, and that it is necessary for airlines to have a brand image and attitude. Also, forming a favorable brand image has a significant impact on brand attitudes. We believe that by presenting basic data to the aviation industry in future research on airline storytelling, we will be able to increase understanding and contribution to development of storytelling marketing in aviation.

Active Coping Strategy Model for Chronic Arthritis : Appling Internal Model of World and Coping Resource (내적모형과 대응자원을 이용한 만성관절염 환자의 적극적 대응전략모형)

  • Mun, Mi-Sook;Lim, Nan-Young
    • Journal of muscle and joint health
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    • v.6 no.1
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    • pp.100-135
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    • 1999
  • Typical symptoms of rheumatic disease affect overall daily living and cause severe stress. Individuals afflicted with rheumatic disease have many illness-related stresses. Pain was the predominantly perceived stress followed by limitation in mobility, difficulties in carrying out activities of daily living. helplessness, dependency on others, threat to self-esteem, interference in social activity, interference in family relationships. difficulties performing at work, and discomfort of the treatment. Patients with chronic arthritis are subjected to long periods of continuous stress, which may require the management by the health care provider. In these cases, the purpose of the nursing is helping to promote health through supporting patient's coping. Therefore, for the nursing intervention to be effective, it is critical to build a theoretical framework that describes stress-coping for chronic arthritis. Thus, the purpose of this dissertation is to present a theoretical framework which describes the stress-coping processes and to empirically test pathos of this framework for the people with chronic arthritis. The foundation upon which this framework is built in the Erickson, Tomlin, and Swain(1983) theory of Modeling and role-Modeling. The subjects were 275 patients with rheumatoid arthritis or osteoarthritis who visited the outpatient clinic. A hypothetical model of stress-coping was tested by covariance structure analysis with PC-LISREL 8.12 program. As a result, the overall fit was good(Chi-square=94.49, P=0.00, RMR=0.067, GFI=0.95, AGFI=0.91, NNFI=0.93, NFI=0.91) for the hypothetical model. The results of hypothesis testing were as follows : Basic need satisfaction had a statistically significant influence on illness-related experience, emotional stress and coping resources. Internal health locus of control had a statistically significant influence on coping resources. However, independent variables(basic need satisfaction, internal health locus of control, illness-related experience, emotional stress and coping resource) did not have significantly influence on coping. And then, the hypothetical model was modified by considering both the theoretical implication and statistical significance of the parameter estimates. The revised model had a better fit to the data(Chi-square=83.11(P=0.00), RMR=0.061, GFI=0.96, AGFI=0.92, NNFI=0.95, NFI=0.92). Hypothesis emerged from the revised model was tested. The results of hypothesis testing were as follows : Basic need satisfaction had a statistically significant influence on illness-related experience, emotional stress and coping resources. Internal health locus of control had a statistically significant influence on illness-related experience and coping resources. Internal health locus of control, illness-related experience, emotional stress and coping resources had a significantly influence on coping. According to the results of this dissertation, basic need satisfaction and internal health locus of control play a central role in appraisal of illness-related experience and coping resources. And illness related-experience, emotional stress, and coping resources affect on coping activities. In summary, nursing interventions to enhance basic need satisfaction and internal health locus of control will decrease illness related experience and emotional stress and increase coping resources. Increased coping resources will prompt coping activities.

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A Study on the Effect of Business Consulting Performance on Organizational Performance - Focusing on Moderating Effect by Organizational Support - (조직성과에 영향을 미치는 컨설팅성과에 관한 연구 - 조직지원의 조절효과 중심으로 -)

  • Kim, Moon-Jun;Chang, Sug-In
    • Management & Information Systems Review
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    • v.35 no.2
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    • pp.185-203
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    • 2016
  • This study set up a study model through a previous study and aims to determine the control effect by organizational support in the effect relationship between consulting performance which is an independent variable and organizational performance which is a dependent variable. To do that, the hypothesis was verified by using statistical programs such as SPSS 20.0 and AMOS 20.0 which can be statistically useful with 511 copies except for the copies which cannot be utilized, over 4 weeks from February $25^{th}$ to March $24^{th}$, 2015, focusing companies located in Seoul, Gyeonggi, Incheon. The hypothesis testing result of the study model set by this study shows that firstly, this study has contributed to establishing an additional theory in the research between consulting performance and organizational performance while it has not been enough for consulting performance and organizational performance in previous studies. Second, although the moderating variable of organizational support in the effect relationship between consulting performance and organizational performance didn't show a partial positive (+) role in the hypothesis testing, more detailed analysis in the survey process and the variety on questionnaire configuration were provided in the variable selection. Third, as consulting performance shows a positive effect on organizational performance, a higher consulting performance gives a direct impact on organizational performance so that a realistic action plan on internalizing and enhancing consulting execution result into organizational performance is aggressively required.

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A Study of Professional Baseball Team Fan's Preference to the Team and the Products of Its Company (프로야구 팬 특성과 소속 기업 팀 및 기업제품에 대한 지지도 연구)

  • Chang, Kyung;Min, Jae-Young
    • Journal of Korean Society of Industrial and Systems Engineering
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    • v.25 no.5
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    • pp.15-21
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    • 2002
  • We studied the relations between variables related to fan's preference in a area of pro-baseball which is the most popular one among pro-sports. The dependent variables are pro-baseball team fan's preference to both the team and the products of the company which has a pro-baseball team, while the independent variables are sex, age, and hometown of fans. Eight hypotheses are constructed with those variables. For testing them a questionnaire was used, whose reliability was checked using Kronbach Alpha. Subjects were 314 college students in a local city. For statistical analysis nonparametric tests like Mann Whitney test, Kruskal-Wallis test, etc were used. Useful and significant results among variables were obtained. Since these results have important implications about management of pro-sports teams and fans and fans Preference to products in a view of sports marketing management, more researches should be done continuously in the future in this area.

Two-sample chi-square test for randomly censored data (임의로 관측중단된 두 표본 자료에 대한 카이제곱 검정방법)

  • 김주한;김정란
    • The Korean Journal of Applied Statistics
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    • v.8 no.2
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    • pp.109-119
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    • 1995
  • A two sample chi-square test is introduced for testing the equality of the distributions of two populations when observations are subject to random censorship. The statistic is appropriate in testing problems where a two-sided alternative is of interest. Under the null hypothesis, the asymptotic distribution of the statistic is a chi-square distribution. We obtain two types of chi-square statistics ; one as a nonnegative definite quadratic form in difference of observed cell probabilities based on the product-limit estimators, the other one as a summation form. Data pertaining to a cancer chemotheray experiment are examined with these statistics.

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Sample size and statistical power consideration for diagnostic test research

  • Kim, Eu Tteum;Park, Choi Kyu;Pak, Son Il
    • Korean Journal of Veterinary Research
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    • v.48 no.3
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    • pp.357-361
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    • 2008
  • Although power analysis is of important tool of research, investigators in veterinary medicine are unaware of the concepts of the statistical power. Two types of error occur in classical hypothesis testing and, those errors should be avoided, if possible. Since power is highly dependent on the sample size, whenever declaring non-statistically significant result they should consider the potential for committing a Type II error in their studies, which refers to the probability of falsely stating that two treatments are equivalent despite true difference between them. Also, sample size determination is one of the most important tasks facing the researcher when planning a diagnostic study, and provides valuable information on the characteristics of a test performance. This type of analysis forms the basis for proper interpretation of test results. The aim of this article was to re-evaluate some selected studies on diagnostic test reported in the domestic veterinary publications to determine the power and necessary sample size for inequality testing to ensure the desired power. Power calculations were illustrated using real-life examples of comparison of a new test and a reference test for detecting antibodies of various animal diseases. Factors affecting to the power were also discussed.