• Title/Summary/Keyword: Test of hypothesis

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Interpretation of Quality Statistics Using Sampling Error (샘플링오차에 의한 품질통계 모형의 해석)

  • Choi, Sung-Woon
    • Journal of the Korea Safety Management & Science
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    • v.10 no.2
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    • pp.205-210
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    • 2008
  • The research interprets the principles of sampling error design for quality statistics models such as hypothesis test, interval estimation, control charts and acceptance sampling. Introducing the proper discussions of the design of significance level according to the use of hypothesis test, then it presents two methods to interpret significance by Neyman-Pearson and Fisher. Second point of the study proposes the design of confidence level for interval estimation by Bayesian confidence set, frequentist confidential set and fiducial interval. Third, the content also indicates the design of type I error and type II error considering both productivity and customer claim for control chart. Finally, the study reflects the design of producer's risk with operating charistictics curve, screening and switch rules for the purpose of purchasing and subcontraction.

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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    • 2005.06a
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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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Testing Homogeneity of Errors in Unbalanced Random Effects Linear Model

  • Ahn, Chul H.
    • Communications for Statistical Applications and Methods
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    • v.8 no.3
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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 Study on Porter Hypothesis : A Distance Function Approach (거리함수접근법을 이용한 Porter 가설에 대한 연구)

  • Lee, Myunghun
    • Environmental and Resource Economics Review
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    • v.16 no.1
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    • pp.171-197
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    • 2007
  • In this paper we provide a methodology that permits test of feasibility of Porter hypothesis under limited data environment by utilizing two types of output distance function: Shephard distance function and directional distance function. The production technology supported by Porter hypothesis is embodied in the directional distance function. The average annual marginal abatement cost for $SO_2$ obtained by estimating the directional distance function is higher than the one obtained with the Shephard distance function by about 50 percent in the Korean electric power industry over the period 1970~1998. This result implies that feasibility of Porter hypothesis depends upon whether investment in production capital and process can bring more than a 50 percent increase in the average productivity.

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Testing Homogeneity for Random Effects in Linear Mixed Model

  • Ahn, Chul H.
    • Communications for Statistical Applications and Methods
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    • v.7 no.2
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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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A Bivariate Two Sample Rank Test for Mixture Distributions

  • Songyong Sim;Seungmin Lee
    • Communications for Statistical Applications and Methods
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    • v.3 no.2
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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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The Role of The Prefrontal Lobes in Scientific Reasoning (과학적 추론 능력의 발달에서 전두엽연합령의 역할)

  • Hur, Myoung;Lawson, Anton E.;Kwon, Young-Ju
    • Journal of The Korean Association For Science Education
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    • v.17 no.4
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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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The Effect of cutaneous Stimulation and Distraction on IV Injection Pain of Chemotherapy Patients (피부자극과 관심전환이 항암제 정맥주사 삽입시 통증감소에 미치는 영향)

  • 박정숙
    • Journal of Korean Academy of Nursing
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    • v.28 no.2
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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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Effect of Ethics Education on Nurse덕s Moral Judgement (윤리교육이 간호사의 도덕판단에 미치는 영향)

  • 김용순
    • Journal of Korean Academy of Nursing
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    • v.30 no.1
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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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Effect of Therapy on Stress and Quality of Life in Patients Undergoing Hemodialysis (음악요법이 혈액투석환자의 스트레스와 삶의 질에 미치는 영향)

  • 김영옥
    • Journal of Korean Academy of Nursing
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    • v.23 no.3
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    • pp.431-452
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    • 1993
  • This study was done to determine the effect of music therapy on stress and quality of life in patients undergoing hemodialysis. The research design was a nonequivalent control group pre -post test design. The subjects consisted of 21 patients who received hemodialysis in two hospitals located in Kwang Ju. The fourteen receiving treatment in one hospital were assigned to the experimental group and the seven in the other hospital to the control group. Data were gathered from December 14, 1992 to January 16, 1993 through questionnaires and physiological measurement. Data were analyzed by the SAS package using frequency, t-test, paired t-test and Pearson Prod uct - Moment Correlation Coefficient. The results of this study are summarized as follows ; 1. There were no significant differences between the two groups on stress scores and quality of life scores before the treatment. 2. The mean score on the psychological stress scale for the patients undergoing hemodialysis was 2.48 out of a maximum mean score of four, the items with high stress scores were “feeling of weakness and annoyed by everything”, “limitation of food”, “limitation of fluid”, “change in skin color” in that order. The psychological category showed the highest stress score followed by developmental, scoioeconomic and physiological stress categories in that order. 3. In the experimental group, post - test diastolic blood pressure decerased significantly(t=3.24, p=0.0064), but in the control group pre and post - test diastolic blood pressure were not different. 4. There was no difference between the two groups on the pre and post -test psychological stress scores or the depression scores. 5. The mean score of quality of life for patients undergoing hemodialysis was 2.75 out of a maxi-mum mean score of five. The category of ‘emtional state’ showed the highest score followed by ‘self - esteem’, ‘physical state and function’, ‘economic life’, ‘relationship with neighbors’ and ‘family relationship’ categories in that order. There was no significant difference in the pre and post - test quality of life scores between the two groups. 6. Hypothesis 1 that patients undergoing hemodialysis who received music therapy would have less stress than patients undergoing hemodialysis who did not receive music therapy is divided into two sub - hypotheses. 1) The first sub-hypothesis that patients undergoing hemodialysis who received music therapy would have less physiological stress than patients undergoing hemodialysis who did not receive music therapy was partly supported. Among three physiological stress indices (pulse, systolic blood pressure, diastolic blood pressure), only diastolic blood pressure decreased significantly after the treatment in the experimental group. 2) The second sub-hypothesis that patients undergoing hemodialysis who received music therapy would have less psychological stress than patients undergoing hemodialysis who did not receive music therapy was not supported. Psychological stress score and depression score were not significantly different before and after the treatment. 7. Hypothesis 2 that patients undergoing hemodialysis who received music therapy would have a higher quality of life score than patients undergoing. hemodialysis who did not received music therapy was not supported. There were no significant changes in the quality of life scores before and after the treatment.

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