• Communications for Statistical Applications and Methods
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• 제9권2호
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• pp.389-399
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• 2002

In order to examine whether the difference between two point estimates of population proportions is statistically significant, data analysts use two techniques. The first is to explore the overlap between two associated confidence intervals. Second method is to test the significance which is introduced at most statistical textbooks under the common assumptions of consistency, asymptotic normality, and asymptotic independence of the estimates. Under the null hypothesis which is two population proportions are equal, the pooled estimator of population proportion is preferred as a point estimator since two independent random samples are considered to be collected from one population. Hence as an alternative method, we could obtain another confidence interval of the difference of the population proportions with using the pooled estimate. We conclude that, among three methods, the overlapped method is under-estimated, and the difference of the population proportions method is over-estimated on the basis of the proposed method.

• 복식문화연구
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• 제6권4호
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• pp.238-246
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• 1998

According to several pilot tests, petite women have their own body proportion which is not simply an overall diminutive reflection of the proportion of Misses sizes. Apparel manufacturers and pattern companies do not consider racial differences nor do they consider petite women's own specific body proportions in their size categories to produce petite garments. The primary objectives of this study was to describe the petite women's body proportions especially the differences between Asian and Caucasian petite women and to compare their body proportions to the average body figure. A physical body measurement chart was developed and revised through a pretest. Sixty subjects, thirty for each group of Asian and Caucasian. They were landmarked using an anthropometric instrument and photographed using the method of somatography for analysis of body proportions. Data were analyzed by t-test for a description of the petite subject's body proportion. The results of this study indicated that the Caucasian subjects had generally a longer lower torso than tehAian subjects in their body proportions. both subject groups had differnt body proportions from the aerage body figure.

• 응용통계연구
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• 제22권4호
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• pp.793-804
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• 2009

두 모비율의 비열등성 시험의 가설에는 두 비율의 차(difference), 비(ratio) 그리고 오즈비(odds ratio)를 이용할 수 있다. Kang과 Chen (2000)이 제안한 두 치료율의 차에 대한 근사 무조건적 검정(Approximate Unconditional test)과 두 치료율의 비에 대한 검정은 실패율을 고려하지 않았으므로 귀무가설이 기각되었을 때 치료율이 비열등하다고 주장할 수 있으나 실패율도 비열등하다고 주장하기에는 문제의 여지가 있다. 오즈비에 대한 검정으로 Chen 등(2000)이 제안한 접근적 검정(Asymptotic test)은 대표본 이론에 근거하여 검정하기 때문에 소표본에서 제 1종의 오류를 범할 확률이 유의수준보다 클 수 있다. 이러한 단점을 보완하기 위해 본 논문에서는 기존의 오즈비 가설에 대한 점근적 검정에 기초하여 근사 무조건적 검정을 제안하였다. 또한 점근적 검정과의 검정력을 비교하고, 근사 무조건적 검정에서 세 가설 간에 검정력을 비교하였다.

• 응용통계연구
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• 제25권3호
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• pp.513-520
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• 2012

An Agresti-Coull type test is considered for the difference of binomial proportions in two doubly sampled data subject to false-positive error. The performance of the test is compared with the likelihood-based tests. It is shown that the Agresti-Coull test has many desirable properties in that it can approximate the nominal significance level with compatible power performance.

• Communications for Statistical Applications and Methods
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• 제23권5호
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• pp.433-444
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• 2016

When we observe binary responses in a cluster (such as rat lab-subjects), they are usually correlated to each other. In clustered binomial counts, the independence assumption is violated and we encounter an extra-variation. In the presence of extra-variation, the ordinary statistical analyses of binomial data are inappropriate to apply. In testing the homogeneity of proportions between several treatment groups, the classical Pearson chi-squared test has a severe flaw in the control of Type I error rates. We focus on modifying the chi-squared statistic by incorporating variance inflation factors. We suggest a method to adjust data in terms of dispersion estimate based on a quasi-likelihood model. We explain the testing procedure via an illustrative example as well as compare the performance of a modified chi-squared test with competitive statistics through a Monte Carlo study.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2006년도 춘계 학술발표회 논문집(II)
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• pp.561-564
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• 2006

The tensile characteristics of four types GFRP (glass fiber reinforced polymer) reinforcing bars with different resin mix proportions and fiber volume fraction were analyzed experimentally. Four types of GFRP reinforcing bars containing approximately 66 or 70% fiber volume fraction with A or B rein mix proportions were considered in this test. All testing procedures including specimens preparation, set-up of test equipments and measuring devices were made according to the recommendations of CSA Standard S806-02. From the test results, it was found that GFRP reinforcing bars containing approximately 70% fiber volume fraction with A rein mix proportion showed the higher tensile strength than that of the others due to the higher fiber volume fraction and proper resin mix proportion.

• 대한토목학회논문집
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• 제29권1A호
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• pp.95-100
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• 2009

본 연구에서는 신속개방형 포장 콘크리트의 적정배합비를 도출하기 위한 실험을 실시하였다. 콘크리트 타설 후 8시간 후 교통개방을 하기 위해 조강제 및 조강시멘트를 사용하였으며 조강제의 적정 혼입량을 결정하기 위해 예비실험을 실시하였다. 이를 바탕으로 시멘트 및 잔골재율을 변수로 공기량, 슬럼프 경시변화, 응결시험, 압축강도, 휨강도 시험을 실시하였다. 실험 결과 8시간 목표 압축강도 21 MPa, 휨강도 3.8 MPa를 만족하는 신속개방형 교통개방 포장 콘크리트의 적정배합비를 도출하였다.

• 한국임상수의학회지
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• 제26권5호
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• pp.401-407
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• 2009

In the previous article in this series we introduced the basic concepts for statistical analysis. The present review introduces hypothesis testing for continuous and categorical data for readers of the veterinary science literature. For the analysis of continuous data, we explained t-test to compare a single mean with a hypothesized value and the difference between two means from two independent samples or between two means arising from paired samples. When the data are categorical variables, the $x^2$ test for association and homogeneity, Fisher's exact test and Yates' continuity correction for small samples, and test for trend, in which at least one of the variables is ordinal is described, together with the worked examples. McNemar test for correlated proportions is also discussed. The topics covered may provide a basic understanding of different approaches for analyzing clinical data.

• Communications for Statistical Applications and Methods
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• 제2권1호
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• pp.112-121
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• 1995

Let $p_1$ and $p_2$ be the proportions of two populations. To test the hypothesis $H_0 : p_1 = p_2$, we usually use the $x^2$ statistic, the large sample binomial statistic Z, and the Generalized Likelihood Ratio statistic-2log $\lambda$developed based on different mathematical rationale, respectively. Since testing the above hypothesis is equivalent to testing whether two populations follow the common Bernoulli distribution, one may also test the hypothesis by comparing 1 with the ratio of each density estimate and the hypothesized common density estimate, called comparison density, which was devised by Parzen(1988). We show that the above traditional test statistics ate actually estimating the measure of distance between the true densities and the common density under $H_0$ by representing them with the comparison density.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 1998년도 봄 학술발표회 논문집(I)
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• pp.237-242
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• 1998

Covering mortar as a filter for permeable polymer concrete is necessary for good permeability from filtration continuously. Therefore, this paper is intended as an evaluation of the mechanical properties and permeability of permeable polymer concrete covered with polymer mortar as a filter. An optimum permeable polymer concrete is selected in various mix proportions, and three different polymer mortars were cast immediately following on the casting of the base permeable polymer concrete. And they are tested for compressive and flexural strengths, adhesion in tension, hardening shrinkage and permeability . From the test results, binder and filler contents in mix proportions had a great influence on the permeability of polymer concretes. The mechanical properties of permeable polymer concretes covered with polymer mortars using crushed stone are superior to other filters, and hardening shrinkage is the smallest in filters. It is apparent that adhesion between the base permeable polymer concrete and polymer mortar is affected by the degree of hardening shrinkage. From this study, proper mix proportions can be recommended in the consideration of properties of the permeable polymer concrete.