• Title/Summary/Keyword: statistical confidence

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Research on the major selection and the career decision of college students (Centering on students studying Dental Technology in D-College) (대학생의 전공선택과 진로결정 분석 - D대학 치기공과 재학생을 중심으로 -)

  • Lee, Hwa-Sik;Bae, Bong-Jin;Chang, Ki-Whan
    • Journal of Technologic Dentistry
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    • v.33 no.4
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    • pp.427-440
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    • 2011
  • Purpose: The following research analyzes the causes of major selection and career decision of students studying dental technology. It is to be used as basic data for the management of career improvement program. Methods: The survey has been processed to 490 college students studying Dental Technology in D-college. Questionnaire consists of major selection confidence sheet (14 items) and career decision confidence sheet (18 items) and was scored with 5-points per question. The collected data was analyzed by the statistical program: SAS V8 for Windows. To test for significance on each item, p < 0.05 has been decided as a standard. Results: The analysis of result about the level of confidence on major selection has valid difference by genders, serving military service or not, experience of studying one more year to enter the college or not, making career decision and grade. The analysis of result about career decision has valid difference by gender, serving military service, career decision, day and night course, age and native place. Conclusion: We develop the career advice program and manage it effectively, the confidence on the major selection and pride about its faculty will be high to dental technology students.

On Prediction Intervals for Binomial Data (이항자료에 대한 예측구간)

  • Ryu, Jea-Bok
    • The Korean Journal of Applied Statistics
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    • v.26 no.6
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    • pp.943-952
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    • 2013
  • Wald, Agresti-Coull, Jeffreys, and Bayes-Laplace methods are commonly used for confidence interval of binomial proportion are applied for prediction intervals. We used coverage probability, mean coverage probability, root mean squared error, and mean expected width for numerical comparisons. From the comparisons, we found that Wald is not proper as for confidence interval and Agresti-Coull is too conservative to differ from confidence interval. However, Jeffrey and Bayes-Laplace are good for prediction interval and Jeffrey is especially desirable as for confidence interval.

The Effect of Self-confidence and stress on University Judo Athletes Performance (대학유도 선수들의 자신감과 스트레스가 경기력에 미치는 영향)

  • Jeon, Ki-Young
    • Journal of Digital Convergence
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    • v.14 no.12
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    • pp.545-553
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    • 2016
  • The purpose of this study is finding out the effect of self-confidence and stress on University Judo Athletes performance. For this study, 249 participants of University Judo team athletes were sampled using convenient sampling method. To process data, AMOS 23.0 and SPSS PC+23.0 Version statistical program for WINDOWS were used and frequency analysis, confirmatory factor analysis, reliability, correlations and structural equation model analysis were conducted. Through such processes and method of the study as above, the results of this study are as follows. Firstly, it was discovered that self-confidence had static influence to athletes performance. Secondly, the stress did not affect the athletes performance.

Confidence Interval for Sensitive Binomial Attribute : Direct Question Method and Indirect Question Method (민감한 이항특성에 대한 신뢰구간 : 직접질문법과 간접질문법)

  • Ryu, Jea-Bok
    • The Korean Journal of Applied Statistics
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    • v.28 no.1
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    • pp.75-82
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    • 2015
  • We discuss confidence intervals for sensitive binomial attributes obtained by a direct question method and indirect question method. The Randomized Response Technique(RRT) by Warner (1965) is an indirect question method that uses a randomization device to reduce the response burden of respondents. We used the mean coverage probability (MCP), root mean squared error (RMSE), and mean expected width (MEW) to compare the confidence intervals by the two methods. The numerical comparisons indicated found that the MEW of RRT is too large and the RRT is so conservative that the MCP exceeds a nominal level(${\alpha}$); therefore, it is necessary to complement these problem in order to increase the utility of the indirect question method.

On prediction intervals for binomial data (이항자료에 대한 예측구간)

  • Ryu, Jea-Bok
    • The Korean Journal of Applied Statistics
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    • v.34 no.4
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    • pp.579-588
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    • 2021
  • Wald, Agresti-Coull, Jeffreys, and Bayes-Laplace methods are commonly used for confidence interval of binomial proportion are applied for prediction intervals. We used coverage probability, mean coverage probability, root mean squared error, and mean expected width for numerical comparisons. From the comparisons, we found that Wald is not proper as for confidence interval and Agresti-Coull is too conservative to differ from confidence interval. However, Jeffrey and Bayes-Laplace are good for prediction interval and Jeffrey is especially desirable as for confidence interval.

Likelihood Based Inference for the Shape Parameter of the Inverse Gaussian Distribution

  • Lee, Woo-Dong;Kang, Sang-Gil;Kim, Dong-Seok
    • Communications for Statistical Applications and Methods
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    • v.15 no.5
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    • pp.655-666
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    • 2008
  • Small sample likelihood based inference for the shape parameter of the inverse Gaussian distribution is the purpose of this paper. When shape parameter is of interest, the signed log-likelihood ratio statistic and the modified signed log-likelihood ratio statistic are derived. Hsieh (1990) gave a statistical inference for the shape parameter based on an exact method. Throughout simulation, we will compare the statistical properties of the proposed statistics to the statistic given by Hsieh (1990) in term of confidence interval and power of test. We also discuss a real data example.

Statistical evaluation of the monotonic models for FRP confined concrete prisms

  • Hosseinpour, Farid;Abdelnaby, Adel E.
    • Advances in concrete construction
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    • v.3 no.3
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    • pp.161-185
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    • 2015
  • FRP confining is a widely used method for seismic retrofitting of concrete columns. Several studies investigated the stress-strain behavior of FRP confined concrete prisms with square and rectangular sections both experimentally and analytically. In some studies, the monotonic stress-strain behavior of confined concrete was investigated and compressive strength models were developed. To study the reliability of these models, thorough statistical tests are required. This paper aims to investigate the reliability of the presented models using statistical tests including t-test, wilcoxon rank sum test, wilcoxon signed rank test and sign test with a level of significance of 5%. Wilk Shapiro test was also employed to evaluate the normality of the data distribution. The results were compared for different cross section and confinement types. To see the accuracy of the models when there were no significant differences between the results, the coefficient of confidence was used.

Radioactive waste sampling for characterisation - A Bayesian upgrade

  • Pyke, Caroline K.;Hiller, Peter J.;Koma, Yoshikazu;Ohki, Keiichi
    • Nuclear Engineering and Technology
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    • v.54 no.1
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    • pp.414-422
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    • 2022
  • Presented in this paper is a methodology for combining a Bayesian statistical approach with Data Quality Objectives (a structured decision-making method) to provide increased levels of confidence in analytical data when approaching a waste boundary. Development of sampling and analysis plans for the characterisation of radioactive waste often use a simple, one pass statistical approach as underpinning for the sampling schedule. Using a Bayesian statistical approach introduces the concept of Prior information giving an adaptive sample strategy based on previous knowledge. This aligns more closely with the iterative approach demanded of the most commonly used structured decision-making tool in this area (Data Quality Objectives) and the potential to provide a more fully underpinned justification than the more traditional statistical approach. The approach described has been developed in a UK regulatory context but is translated to a waste stream from the Fukushima Daiichi Nuclear Power Station to demonstrate how the methodology can be applied in this context to support decision making regarding the ultimate disposal option for radioactive waste in a more global context.

A Study on the Packing Friction Estimation of Power-Operated Valves in Nuclear Power Plants (원전 동력구동 밸브 패킹 마찰력 예측에 관한 연구)

  • Ryu, Dong Hwa;Lee, Young Shin
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.37 no.11
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    • pp.1053-1060
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    • 2013
  • The purpose of this study is to estimate the packing friction of power-operated valve in nuclear power plants. The roll of packing in valve is preventing leakage through stem. Packing friction is highly depend on gland nut tightness which means higher reliability in sealing is lower operability. For the estimation of friction, we used statistical analysis and experimental analysis. In experimental approach, we have performed packing fY test and applied it to valve field test. In statistical approach, we have used 10 years DB of safety-related valve in nuclear power plant and analyzed packing friction based on confidence interval of sample. The comparison of two results shows that statistical analysis for packing friction are more accurate than fY analysis even though both approach have error compared to measured value but we confirmed that statistical approach is proper way to estimate packing friction.

The estimation of the productivity in adjacent water fisheries (연근해어업 업종별 생산성 추정에 관한 연구)

  • Park, Cheol-Hyung
    • The Journal of Fisheries Business Administration
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    • v.45 no.1
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    • pp.63-77
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    • 2014
  • This study is to estimate the recent changes in total factor productivity of 15 Korean adjacent water fisheries based on Malmquist productivity indices. The study adopted both input and output oriented productivity measures utilizing a hyperbola distance function. In addition to this point, the study also calculated the 95% confidence interval for the various components of the productivities in order to access the statistical significance of estimates using 2000 times of re-sampling process through the smoothed bootstraping. The results of the study showed us that there was 18% reduction in the overall total factor productivity during the study period from 2007 to 2011, which turned out to be 5% of annual decrease in productivity. The study found that the main reason of this decrease in total productivity is about 22% downward shift of a fisheries production function due to recent conditions of a devastated fishing ground. When we evaluated the statistical significance of changes in technical efficiency combining both pure technical and scale efficiency based on the 95% confidence intervals, we could not find any evidence of changes in those components of total factor productivity. When we accessed the productivity of the each of 15 adjacent water fisheries methods, only the large danish seine fisheries showed us about 7% increase in productivity. Even though the large trawling and the large tow-boat trawling revealed no changes in productivity, all of the other 12 fisheries suffered the decreases in productivities.