• Communications for Statistical Applications and Methods
• /
• v.13 no.2
• /
• pp.205-217
• /
• 2006

In this paper, we consider the problem of testing for a change of the parameter function ${\theta}(t)$ that may have a discontinuity at some unknown point ${\tau}$. We introduce a varying-h moving estimate to test the null hypothesis that ${\theta}(t)$ is continuous against the alternative that ${\theta}({\tau}-){\neq}{\theta}({\tau}+)$. Simulation results are provided for illustration.

• Journal of Construction Engineering and Project Management
• /
• v.6 no.1
• /
• pp.20-25
• /
• 2016

With the multitude of variables that may play a role in a company's Lean journey, it is becoming more understood that leadership plays a significant role in implementing lean principles on construction projects. The goal of this research is to investigate the relationship between leadership and Lean Construction implementation. The research uses a quantitative research in which a survey was conducted, followed by a statistical analysis to test the hypothesis. Through the statistical analysis of survey data, the research finds that there is positive relation between the level of transformational leadership and the effectiveness of lean implementation. When an organization is implementing organizational change like Lean, traits of leaders must not be underestimated. The study findings may contribute to the knowledge of lean construction leadership by bridging the gap between leadership and the effectiveness of lean implementation.

• Transactions on Electrical and Electronic Materials
• /
• v.13 no.3
• /
• pp.129-135
• /
• 2012

A number of surface mount technology (SMT) process variables including land design are considered for minimizing tombstone defect in flexible printed circuit assembly in high volume manufacturing. As SMT chip components have been reduced over the past years with their weights in milligrams, the torque that once helped self-centering of chips, gears to tombstone defects. In this paper, we have investigated the correlation of the assembly process variables with respect to the tombstone defect by employing statistically designed experiment. After the statistical analysis is performed, we have setup hypotheses for the root causes of tombstone defect and derived main effects and interactions of the process parameters affecting the hypothesis. Based on the designed experiments, statistical analysis was performed to investigate significant process variable for the purpose of process control in flexible printed circuit manufacturing area. Finally, we provide beneficial suggestions for find-pitch PCB design, screen printing process, chip-mounting process, and reflow process to minimize the tombstone defects.

• Journal of the Korean Statistical Society
• /
• v.19 no.2
• /
• pp.128-138
• /
• 1990

In this paper we study the properties of nonparametric tests for testing the null hypothesis of no changes against one sided and two sideds alternatives in scale parameter at unknown point. We first propose two types of nonparametric tests based on linear rank statistics and rank-like statistics, respectively. For these statistics, we drive the asymptotic distributions under the null and contiguous alternatives. The main theoreticla tools used for derivation are the stochastic process representation of the test staistic and the Brownian bridge approximation. We evaluate the Pitman efficiencies of the test for the contiguous alternatives, and also compute empirical power by Monte Carlo simulation.

• Communications for Statistical Applications and Methods
• /
• v.23 no.3
• /
• pp.215-230
• /
• 2016

The powers of some tests for independence hypothesis against positive (negative) quadrant dependence in generalized Farlie-Gumbel-Morgenstern distribution are compared graphically by simulation. Some of these tests are usual linear rank tests of independence. Two other possible rank tests of independence are locally most powerful rank test and a powerful nonparametric test based on the $Cram{\acute{e}}r-von$ Mises statistic. We also evaluate the empirical power of the class of distribution-free tests proposed by Kochar and Gupta (1987) based on the asymptotic distribution of a U-statistic and the test statistic proposed by $G{\ddot{u}}ven$ and Kotz (2008) in generalized Farlie-Gumbel-Morgenstern distribution. Tests of independence are also compared for sample sizes n = 20, 30, 50, empirically. Finally, we apply two examples to illustrate the results.

• Communications for Statistical Applications and Methods
• /
• v.23 no.6
• /
• pp.563-574
• /
• 2016

In this study, we propose several simultaneous tests to detect the difference between means and variances for the two-sample problem when the underlying distribution is normal. For this, we apply the likelihood ratio principle and propose a likelihood ratio test. We then consider a union-intersection test after identifying the likelihood statistic, a product of two individual likelihood statistics, to test the individual sub-null hypotheses. By noting that the union-intersection test can be considered a simultaneous test with combination function, also we propose simultaneous tests with combination functions to combine individual tests for each sub-null hypothesis. We apply the permutation principle to obtain the null distributions. We then provide an example to illustrate our proposed procedure and compare the efficiency among the proposed tests through a simulation study. We discuss some interesting features related to the simultaneous test as concluding remarks. Finally we show the expression of the likelihood ratio statistic with a product of two individual likelihood ratio statistics.

• Communications for Statistical Applications and Methods
• /
• v.26 no.1
• /
• pp.57-67
• /
• 2019

Income distribution is a major concern in economic theory. In regional economics, it is often of interest to compare income distributions in different regions. Traditional methods often compare the income inequality of different regions by assuming parametric forms of the income distributions, or using summary statistics like the Gini coefficient. In this paper, we propose a nonparametric procedure to test for heterogeneity in income distributions among different regions, and a K-means clustering procedure for clustering income distributions based on energy distance. In simulation studies, it is shown that the energy distance based method has competitive results with other common methods in hypothesis testing, and the energy distance based clustering method performs well in the clustering problem. The proposed approaches are applied in analyzing data from China Health and Nutrition Survey 2011. The results indicate that there are significant differences among income distributions of the 12 provinces in the dataset. After applying a 4-means clustering algorithm, we obtained the clustering results of the income distributions in the 12 provinces.

• Journal of the Semiconductor & Display Technology
• /
• v.20 no.4
• /
• pp.114-118
• /
• 2021

In this research, the dimensional error of the measured specimen according to the measurement method was analyzed for the length, angle, radius of curvature and diameter using a projector which is used in industry. One-way analysis was performed on each data tested 30 times using a statistical technique. Through the experiment, it was found that an error occurred in each data when measuring the length and radius of curvature according to the measurement method, and the null hypothesis that no error occurred when measuring the angle and length was established. Based on this experimental data, the automatic measurement when measuring the projector causes less measurement error, so automatic measurement is recommended when measuring a small product. Also, an optimal measuring method is suggested for securing reliability on formulations of measurement automation.

• The Korean Journal of Applied Statistics
• /
• v.27 no.4
• /
• pp.645-653
• /
• 2014

P-value is the probability of observing a current sample and possibly other samples departing equally or more extremely from the null hypothesis toward postulated alternative hypothesis. When p-value is less than a certain level called ${\alpha}$(= 0:05), researchers claim that the alternative hypothesis is supported empirically. Unfortunately, some findings discovered in that way are not reproducible, partly because the p-value itself is a statistic vulnerable to random variation. Boos and Stefanski (2011) suggests calculating the upper limit of p-value in hypothesis testing, using a bootstrap predictive distribution. To determine the sample size of a replication study, this study proposes thought experiments by simulating boosted bootstrap samples of different sizes from given observations. The method is illustrated for the cases of two-group comparison and multiple linear regression. This study also addresses the reproducibility of the points in the given 95% confidence interval. Numerical examples show that the center point is covered by 95% confidence intervals generated from bootstrap resamples. However, end points are covered with a 50% chance. Hence this study draws the graph of the reproducibility rate for each parameter in the confidence interval.

• Industry Promotion Research
• /
• v.3 no.1
• /
• pp.13-31
• /
• 2018

The purpose of this study is to investigate the effect of organizational culture on organization and organizational performance, and it was targeting for 350 public officials (local governments, foundation under local governments, public corporation) who research work and consulting were implemented for. When it comes to the response to questionnaires, 313 copies out of 350 were verified on the research hypothesis of the research model by using statistical package programs of SPSS 20.0 and AMOS 20.0. Results of the research hypothesis on research model show that firstly, regarding the research hypothesis 1 that the organizational culture of public organization will have a positive (+) significant effect on learning organization, the organizational culture recognized by the organizational members of public organizations showed a positive influence on the learning organization. In other words, it showed that the organizational culture recognized by the organization members of public organizations is a major factor in building a learning organization. Secondly, regarding the research hypothesis 2, the result of the relationship between organizational culture and organizational performance, that the organizational culture recognized by the organizational members of the public sector showed a positive influence and it implies the importance of recognizing and transforming the organizational culture of public organizations to improve organizational performance of public organizations. Thirdly, regarding the research hypothesis 3, the organizational culture recognized by the organizational members of public organizations showed an influence on organizational performance and also showed apositive(+) influence on organizational performance through learning organization. As the organizational culture recognized by the organization members in the public sectoris influencing the organizational performance through the learning organization, various implementation plans are required to improve organizational culture, improving learning organization, and improving organizational performance in accordance with the characteristics of public organizations.