• 제목/요약/키워드: Test hypothesis

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A Study on the Analysis and Identification of Seafarers' Skill-Rule-Knowledge Inherent in Maritime Accidents

  • Yim, Jeong-bin
    • 해양환경안전학회지
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    • 제23권3호
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    • pp.224-230
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    • 2017
  • The purpose of this study is to classify the deficient abilities of seafarers into SRK (Skill, Rule, and Knowledge) and analyze and identify the SRK by the type of accident and ship. Experimental data used the SRK cumulative frequency for 1,606 marine accident records and two-way ANOVA and t-test were used for the analysis tools. The results of two-way ANOVA showed that it is possible to identify the deficient abilities by using the cumulative frequency of SRK in both accident and ship types. As a result of the t-test, the adoption of the null hypothesis (H=0) that the mean of two pairs is equal and the rejection of the null hypothesis (H=1) were 29.2 % and 70.8 %, respectively. For the ship type, H=0 is 33.3 % and H=1 is 66.7 %. Through this study, it was found that about 70 % of the deficient abilities of seafarers inherent in maritime accidents can be identified using the proposed method.

Multipath detection in carrier phase differential GPS

  • Seo, Jae-Won;Lee, Hyung-Keun;Lee, Jang-Gyu;Park, Chan-Gook
    • 제어로봇시스템학회:학술대회논문집
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    • 제어로봇시스템학회 2005년도 ICCAS
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    • pp.1239-1243
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    • 2005
  • A multipath mitigation method using the fault detection and isolation technique is proposed for the CDGPS. The base station is assumed to be immune to the effect of the multipath. With this reasonable assumption, the effect of multipath in moving station is mitigated. For that, the double difference measurement is produced, and then another additional difference between code pseudorange and acclumulated carrier phase is calculated. The test statistic is constituted with those differences. The hypothesis testing is applied to that test statistic. The proposed test statistic makes use of the effect of multipath in code pseudoranges and it does not use time differences. Therefore the detection ability for multipath is improved in most environments. However, the increased number of differences makes the measurement noises larger. The performance of the method is compared with that of the conventional parity space method with code pseudorange.

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Designing Statistical Test for Mean of Random Profiles

  • Bahri, Mehrab;Hadi-Vencheh, Abdollah
    • Industrial Engineering and Management Systems
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    • 제15권4호
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    • pp.432-445
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    • 2016
  • A random profile is the result of a process, the output of which is a function instead of a scalar or vector quantity. In the nature of these objects, two main dimensions of "functionality" and "randomness" can be recognized. Valuable researches have been conducted to present control charts for monitoring such processes in which a regression approach has been applied by focusing on "randomness" of profiles. Performing other statistical techniques such as hypothesis testing for different parameters, comparing parameters of two populations, ANOVA, DOE, etc. has been postponed thus far, because the "functional" nature of profiles is ignored. In this paper, first, some needed theorems are proven with an applied approach, so that be understandable for an engineer which is unfamiliar with advanced mathematical analysis. Then, as an application of that, a statistical test is designed for mean of continuous random profiles. Finally, using experimental operating characteristic curves obtained in computer simulation, it is demonstrated that the presented tests are properly able to recognize deviations in the null hypothesis.

Testing Homogeneity for Random Effects in Linear Mixed Model

  • Ahn, Chul H.
    • Communications for Statistical Applications and Methods
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    • 제7권2호
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    • pp.403-414
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    • 2000
  • A diagnostic tool for testing homogeneity for random effects is proposed in unbalanced linear mixed model based on score statistic. The finite sample behavior of the test statistic is examined using Monte Carlo experiments examine the chi-square approximation of the test statistic under the null hypothesis.

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Testing Homogeneity of Errors in Unbalanced Random Effects Linear Model

  • Ahn, Chul H.
    • Communications for Statistical Applications and Methods
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    • 제8권3호
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    • pp.603-613
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    • 2001
  • A test based on score statistic is derived for detecting homoscedasticity of errors in unbalanced random effects linear model. A small simulation study is performed to investigate the finite sample behaviour of the test statistic which is known to have an asymptotic chi-square distribution under the null hypothesis.

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A Bivariate Two Sample Rank Test for Mixture Distributions

  • Songyong Sim;Seungmin Lee
    • Communications for Statistical Applications and Methods
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    • 제3권2호
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    • pp.197-204
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    • 1996
  • We consider a two sample rank test for a bivariate mixture distribution based on Johnson's quantile score. The test statistic is simple to calculate and the exact distribution under the null hypothesis is obtained. A numerical example is given.

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과학적 추론 능력의 발달에서 전두엽연합령의 역할 (The Role of The Prefrontal Lobes in Scientific Reasoning)

  • 허명;;권용주
    • 한국과학교육학회지
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    • 제17권4호
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    • pp.525-540
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    • 1997
  • The present study tested the hypothesis that maturation of the prefrontal lobes is a crucial factor determining the performance of scientific reasoning tasks, Functions of the prefrontal lobes, such as activating relevant information, sequential planning and monitoring, and inhibiting irrelevant information, are related thinking patterns with scientific reasoning. Therefore, we inferred the idea that the prefrontal lobes play an important role in scientific reasoning. To test the hypothesis. the present study investigated a prefrontal lobe patient's task solving procedures in scientific reasoning tasks and the correlation and regression analysis between a test of prefrontal lobe function and two scientific reasoning tasks, The perseverative errors in the Wisconsin Card Sorting Test(WCST) was used as a measure of the prefrontal lobe function, The Melinark Type Task and the Classroom Test of Scientific Reasoning were used as measures of scientific reasoning abilities. Ages and Group Embedded Figure Test were also used as measures of two alternative hypotheses, general maturation and field independency respectively. The prefrontal lobe patient showed a crucial deficiency in solving scientific reasoning tasks. In the tasks, the patient could not used the reasoning of If... and... then... therefore pattern. In correlation study, the perseveration errors of the WCST showed a significantly negative correlation with two scientific reasoning tasks. Multiple regression study also showed that the perseveration errors measured as a function of the prefrontal lobes have more contribution to scientific reasoning ability than contributions of alternative hypotheses. Therefore, the present study supported the hypothesis that prefrontal lobes play a crucial role in scientific reasoning ability, What function of the prefrontal lobes do play crucial role in scientific reasoning? The present study provided an explanation for the question, which inhibiting ability of the prefrontal lobes is responsible for the scientific reasoning ability, in a part at least. That is, perseverative tendency in task-solving procedures causes a deficiency of an ability to inhibit the wrong information to solve a task. The present study provided a possibility of neuropsychological approach in science education research. The present study also showed an importance of the prefrontal lobe development in the performance of scientific reasoning task.

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피부자극과 관심전환이 항암제 정맥주사 삽입시 통증감소에 미치는 영향 (The Effect of cutaneous Stimulation and Distraction on IV Injection Pain of Chemotherapy Patients)

  • 박정숙
    • 대한간호학회지
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    • 제28권2호
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    • pp.303-318
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    • 1998
  • Cutaneous stimulation and distraction are independent nursing interventions used in various painful conditions, which is explained by gate control theory. This study was aimed at identifying the effect of cutaneous stimulation, distraction and combination of cutaneous stimulation and distraction on the reduction of intravenous injection pain levels of chemotherapy patients. Repeated measurement post test research design was used for one group. Fifty-three cancer patients who received intravenous chemotherapy regulary in outpatient injection rooms of D medical center and Y medical center in Taegu were studied from June 23, 1997 to July 12, 1997. First the intravenous injection pain level of the control period was measured. Second, the intravenous injection pain level of the experimental period using cutaneous stimulation was measured. Third, the intravenous injection pain level of the experimental period using distraction was messured. Fourth, the intravenous injection pain level of the experimental period using a combination of cutaneous stimulation and distraction was measured. The instruments used for this study were a visual analogue pain scale as subjective pain measurement and an objective pain behavior checklist. Analysis of data was done by use of repeated measure ANOVA, bonferni, t-test, and F-test. The results of this study were summerized as follows : 1) The first hypothesis that the subjective pain score of intraveneous injection pain in the experimental period with cutaneous stimulation will be lower than in the control period was rejected. 2) The second hypothesis that the objective pain behavior score of intravenous injection pain in the experimental period with cutaneous stimulation will be lower than in the control period was accepted(F=24.23, p=0.0001, Bornferni p<.05). 3) The third hypothesis that the subjective pain score of intraveneous injection pain in the experimental period with distraction will be lower than in the control period was rejected. 4) The fourth hypothesis that the objective pain score of intravenous injection pain in the experimental period with distraction will be lower than in the control period was accepted(F=24.23, p=0.0001, Bornferni p<.05). 5) The fifth hypothesis that the subjective pain score of intravenous injection pain in the experimental period with combination of cutaneous stimulation and distraction will be lower than in the control period was accepted(F=3.04, p=0.031, Bonferni p<.05). 6) The sixth hypothesis that the objective pain score of intravenous injection pain in the experimental period with combination of cutaneous stimulation and distraction will be lower than in the control period was accepted(F=24.23, p=0.0001, Bonferni p<.05).

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윤리교육이 간호사의 도덕판단에 미치는 영향 (Effect of Ethics Education on Nurse덕s Moral Judgement)

  • 김용순
    • 대한간호학회지
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    • 제30권1호
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    • pp.183-193
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    • 2000
  • This main purpose of this study was to assess the effects of two different types of ethics education on the moral judgement of clinical nurses. One type was free discussions among nurses with given specific moral issues and the other type was discussions guided by experts on specific moral issues. The study employed a quasi-experimental, nonequivalent pre test-post test design using two different control groups. The conceptual framework of the study was derived from the Kohlberg′s Moral Development Theory (1969) and the Greipp′s Ethical Decision-Making Model (1992). The data was collected during the period of October 14 through December 15, 1998. Sample consists of 32 nurses working in the ICU who met research criteria. 16 nurses were assigned to the free discussion group and 16 nurses to the group for the guided discussion with experts group. For the pre-test, the DIT which was developed by Rest (1984) and JAND by Ketefian (1998) were used with some modification by the author. After the education, only JAND was used to assess the changes in moral judgement. The collected data was analysed using SPSS PC program. The findings are as follows: 1. There was no significant difference between two groups in their general characteristics. Only difference which was statistically significant between two groups was that realistic score on Case 3/Medical Research and Autopsy was higher in the free discussion group. 2. Hypothesis 1: "There will be a difference on the moral judgement of nurses before and after they receive an ethics education". This hypothesis was supported partially. Those who had low scores on moral judgement before the education tended to have higher scores after the education on the same issues. And, after the education, the nurses tend to give lower scores on the dilemmas they had experienced frequently at work; while giving higher scores on those dilemmas they had no prior experience. 3. Hypothesis 2: "The effect of education may differ depended upon the moral development index [P(%)] score of nurses". The effect of education was different depend on moral development level. The group who′s P(%) scores was low at the pretest has higher scores in realistic moral judgement after the education, while the groups with middle or high P(%) scores went down after the education. These changes were statistically significant in some cases, thus, the Hypothesis 2 was partially supported 4. Hypothesis 3: "The method of ethics education will have different effects on the moral judgement of nurses". Even though several nurses attended the guided discussion stated that the education program broadend their perspectives the difference between two groups was not significant and this hypothesis was not supported. In conclusion, both types of ethics education had helped the nurses to acquire the skills to deal some nursing dilemmas. The effects of ethics education may differ according to the moral development index - P(%) score. However, because of some of the limitations of this study, mainly small sample size, short term education, unable to control other variables which may affect moral judgement of nurses, further research is warranted.er research is warranted.

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음악요법이 경정맥요로조영 검사시 환자의 불안에미치는 영향 (Effects of Music Therapy on Anxiety of Intravenous Urology Patients)

  • 여진동;고인호
    • 한국방사선학회논문지
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    • 제11권2호
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    • pp.95-107
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    • 2017
  • 본 연구는 음악요법이 경정맥요로조영 검사로 인한 불안정도와 검사 시 불편감에 미치는 음악요법의 효과를 파악하고자 시도된 비동등성 대조군 사전-사후 실험설계의 유사 실험이다. "음악요법을 받은 군은 음악요법을 받지 않는 군보다 검사 중 불안 점수가 낮을 것이다"는 음악요법 실시 후 실험군의 불안점수가 대조군의 불안점수와 비교하여 유의한 차이가 있어 채택되었다. "음악요법을 받은 군은 음악요법을 받지 않는 군보다 검사 후 활력징후가 낮을 것이다"는 수축기 혈압, 이완기혈압에 대한 가설은 기각되었지만, 맥박에서는 유의 한 차이가 나타나 부분적으로 채택 되었다. "음악요법을 받은 군은 음악요법을 받지 않는 군보다 주간 적 불편감이 낮을 것이다"는 두 집단 간의 유의한 차이를 보였다. 한편 주관적인 불편 감의 하부요인 중 긴장감 에서만 유의한 차이가 있었으며, 동통, 어지러움, 공포감에서는 유의한 차이가 없었다. 이상의 연구결과로 볼 때 음악요법은 경정맥요로조영 검사 중 환자의 상태불안을 감소시킬 수 있는 유용한 대체검사법이 될 수 있을 것이라고 생각된다.