• 응용통계연구
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• 제17권3호
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• pp.393-402
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• 2004

본 연구에서는 통계청에서 매년 실시하고 있는 사업체 기초통계조사 자료를 조사모집단으로 하여 전자상거래 시장규모, e-비즈니스 투자규모 뿐만 아니라, 전자상거래 및 e-비즈니스 일반현황을 동시에 파악하기 위한 표본설계방안을 제안하고자 한다.

• 한국식생활문화학회지
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• 제26권3호
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• pp.279-282
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• 2011

We evaluated the sensory characteristics of Gangjung base obtained from various manufacturers, using a sensory descriptive analysis. Significant differences were observed for all sensory attributes of Gangjung samples with the exception of 'toothpacking'. Sample A showed high intensities for 'external color', 'external roughness', 'sweetness', 'toasted soybean powder flavor', 'crispness', 'fracturability', 'oiliness', and 'loose particles,' whereas it had low intensities for 'rice flour flavor', 'hardness', and 'toughness' compared to those of other samples. Sample B had more 'sourness', 'butyric acid flavor', 'fermented rice flavor', and 'degree of melting' but lower 'air cell size', 'fracturability', and 'flake roughness'. Sample C showed high intensities for 'expansion', 'hardness', 'crispness', and 'flake roughness', whereas sample D showed low intensities for 'expansion' and 'sourness'. These results indicate that Gangjung base samples are markedly different depending on the manufacturer.

• 한국수학교육학회지시리즈A:수학교육
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• 제42권3호
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• pp.419-423
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• 2003

The main purpose of this paper is to investigate effects of skewness and kurtosis on the one-sample test. We have found that type I error brought about a little bit change which is ignorable in relation to kurtosis. Also the change of type I error was completely based on skewness under the same size of the sample. We conclude that using t-test is more similar to robust than using z-test. In introductory statistics classes where data analysis includes techniques for detecting skewness, we recommend the t-test when skewness is smaller than the value 1 to the one-sample test for a mean when the variances is unknown using the probability of a type I error as the criterion of interest.

• Journal of the Korean Data and Information Science Society
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• 제25권3호
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• pp.633-641
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• 2014

The exponential distibution is one of the most popular distributions in analyzing the lifetime data. In this paper, we propose multiply Type I hybrid censoring. And this paper presents the statistical inference on the scale parameter for the exponential distribution when samples are multiply Type I hybrid censoring. The scale parameter is estimated by approximate maximum likelihood estimation methods using two different Taylor series expansion types ($AMLE_I$, $AMLE_{II}$). We also obtain the maximum likelihood estimator (MLE) of the scale parameter ${\sigma}$ under the proposed multiply Type I hybrid censored samples. We compare the estimators in the sense of the root mean square error (RMSE). The simulation procedure is repeated 10,000 times for the sample size n=20 and 40 and various censored schemes. The $AMLE_{II}$ is better than $AMLE_I$ in the sense of the RMSE.

• Journal of the Korean Data and Information Science Society
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• 제25권6호
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• pp.1581-1589
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• 2014

In this paper, we consider maximum likelihood estimators of the location and scale parameters for the half-logistic distribution when samples are multiply Type I hybrid censored. The scale parameter is estimated by approximate maximum likelihood estimation methods using two different Taylor series expansion types ($\hat{\sigma}_I$, $\hat{\sigma}_{II}$). We compare the estimators in the sense of the root mean square error (RMSE). The simulation procedure is repeated 10,000 times for the sample size n=20 and 40 and various censored schemes. The approximate MLE of the second type is better than that of the first type in the sense of the RMSE. Further an illustrative example with the real data is presented.

• 품질경영학회지
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• 제30권4호
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• pp.1-14
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• 2002

Traditional SPC techniques are looking out variation of process by fixed sampling interval and fixed sample size about every hour, the process of in-control or out-of-control couldn't be detected actually when the sample points are plotted near control limits, and it takes no notice of expense concerned with such sample points. In this paper, to overcome that, consider VSI(variable sampling interval) EWMA control charts which VSI method is applied. The VSI control charts use a short sampling internal if previous sample points are plotted near control limits, then the process has high probability of out-of-control. But it uses a long sampling interval if they are plotted near centerline of the control chart, since process has high possibility of in-control. And then a comparison and analysis between FSI(fixed sampling interval) and VSI EWMA in the statistical aspect and economic aspect is studied. Finally, we show that VSI EWMA control chart is more efficient than FSI EWMA control chart in the both aspects.

• Communications for Statistical Applications and Methods
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• 제28권5호
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• pp.463-475
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• 2021

Desgagné and de Micheaux (2018) proposed an alternative univariate normality test to the Jarque-Bera test. The proposed statistic is based on the sample second power skewness and kurtosis while the Jarque-Bera statistic uses sample Pearson's skewness and kurtosis that are the third and fourth standardized sample moments, respectively. In this paper, we generalize their statistic to a multivariate version based on orthogonalization or an empirical standardization of data. The proposed multivariate statistic follows chi-squared distribution approximately. A simulation study shows that the proposed statistic has good control of type I error even for a very small sample size when critical values from the approximate distribution are used. It has comparable power to the multivariate version of the Jarque-Bera test with exactly the same idea of the orthogonalization. It also shows much better power for some mixed normal alternatives.

• 대한가정학회지
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• 제49권10호
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• pp.49-56
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• 2011

The purpose of this study is to research the difference between the size suggested by brand uniforms and the size suitable for high school girls. We compared and analyzed the size system of brand uniforms after researching the wearing conditions of uniforms of 4 brands (A, B, C, D) in order to establish a size system of brand uniforms that fits different body types of teenagers. First, we conduct research on the actual condition of brand uniforms worn by high school girls, and investigate unsatisfactory factors and problems. Second, we actually measure the uniform size of each brand and analyze measurement differences between each brand. Our results show each brand uniform has different size specifications and the importance of appropriate size specification is greater as students select uniform based on design and brand awareness rather than body size. Compared with the average body size the skirt and especially the blouse is much smaller with no extra room compared with standard size 85 blouses and size 71 skirts. Therefore, the adjustment of size specification is needed in brand school uniforms. However, a larger scale investigation is needed as this study was conducted with a limited sample size.

• Journal of Hospice and Palliative Care
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• 제13권1호
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• pp.1-6
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• 2010

임상시험은 인간을 대상으로 약물 또는 치료법의 효과를 검증하는 것을 목적으로 하고 있다. 성공적인 임상시험을 위해서는 단순한 자료분석에만 통계의 이용을 제한하지 않고 다양한 영역으로 활용의 폭을 넓히는 것이 필요하다. 연구계획단계에서부터 구체적이고 체계적으로 통계의 활용을 고려하기 위해 효과에 대한 정의, 적정한 표본크기 산정, 통계분석 방법 등 전반적인 통계의 응용을 고찰한다.

• Communications for Statistical Applications and Methods
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• 제5권2호
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• pp.539-557
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• 1998

This article is concerned with the problem of estimating the mean of a one-parameter exponential family through sequential sampling in three stages under quadratic error loss. This more general framework differs from those considered by Hall (1981) and others. The differences are : (i) the estimator and the final stage sample size are dependent; and (ii) second order approximation of a continuously differentiable function of the final stage sample size permits evaluation of the asymptotic regret through higher order moments. In particular, the asymptotic regret can be expressed as a function of both the skewness $\rho$ and the kurtosis $\beta$ of the underlying distribution. The conditions on $\rho$ and $\beta$ for which negative regret is expected are discussed. Further results concerning the stopping variable N are also presented. We also supplement our theoretical findings wish simulation results to provide a feel for the triple sampling procedure presented in this study.