• Communications for Statistical Applications and Methods
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• v.29 no.4
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• pp.403-411
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• 2022

This article presents an independence test between pairs of interval censored failure times. The Mantel-Haenszel test is commonly applied to test the independence between two categorical variables accompanied with a strata variable. Hsu and Prentice (1996) applied a Mantel-Haenszel test to the sequence of 2 × 2 tables formed at the grids which are composed of failure times. In this article, due to unknown failure times, the suitable grid points should be determined and the status of failure and at risk are estimated at those grid points. We also consider a weighted test statistic to bring a more powerful test. Simulation studies are performed to evaluate the power of test statistics under finite samples. The method is applied to analyze two real data sets, mastitis data from milk cows and an age-related eye disease study.

• The Korean Journal of Applied Statistics
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• v.11 no.2
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• pp.257-268
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• 1998

Many epidemiological studies investigate whether an association exists between a binary risk factor X and a binary response variable Y. They analyse whether an observed association between X and Y persists when the level of another factor Z that might influence the association is controlled. This involves testing conditional independence of X and Y controlling for Z. The Mantel-Haenszel test is most widely used to test conditional independence for sparse tables. But if the association between X and Y varies along the levels of Z, Mantel-Haenszel test has a low power problem. In this study, we propose an alternative test procedure which overcomes the low power problem in that case. We find out the null distribution of the alternative test statistic and compare its performance with the Mantel-Haenszel test by simulation.

• Communications for Statistical Applications and Methods
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• v.8 no.1
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• pp.51-63
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• 2001

We are interested in the conditional independence in sparse $2\tims2\tims$K tables with very rare cell counts. The most popular test is Cochran-Mantel-Haenszel statistic when sample sizes are moderately large enough to guarantee the chi-square approximation. We will consider jackknifing the CMH test and also suggest an approximate normal distribution for the standardized jackknifed CMH statistic. The main focus of this paper is to improve the chi-squared approximation to the CMH test by using the asymptotic normality of the jackknifed CMH test when sample sizes are very sparse but K and N$\infty$. The performance of the proposed jackknifed test, in the sense of significance level control and power, will be compared with that of the CMH test through a Monte Carlo study.

• Proceedings of the Korea Water Resources Association Conference
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• 2007.05a
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• pp.246-252
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• 2007

농업 비점오염원으로부터의 수질 보전이나 수자원 관리는 유역단위로 하여 농업적 관리뿐만 아니라 수질 관리 및 수자원 관리를 위해서도 유역단위 특히, 소유역의 토양특성을 포괄하는 단위로 체계적으로 분류할 필요성이 있다. 우리나라의 남서쪽에 위치한 영산강유역의 50개 소유역을 대상으로 토양도, 지형도, 하천도 및 유역도를 이용하여 만곡도, 산림의 비율, 평탄지의 비율, 다른 소유역으로부터의 유입이 있는지의 여부 등 토양학적으로 중요한 4개의 특성을 가지고 군집분석을 수행하였다. 그 결과 5개의 군으로 구분할 수 있었으며, 이 구분의 적합도를 검정하기 위하여 Mantel test를 한 결과 r = 0.81825로 나타나 적합하다는 결론을 얻었다. 이와 같이 토양과 지형특성을 포괄하는 소유역의 분류 및 유사성에 따른 그룹화는 농업에서의 최적영농관리나 오염물질에 따른 수질관리, 수문모형의 적용성 확대 및 수자원 관리에 합리적 유용성을 제공할 것이며 체계적 관리의 밑바탕이 될 것이다.

• Journal of Korean Society of Forest Science
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• v.103 no.1
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• pp.1-11
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• 2014

This study was conducted to investigate the changes understory vegetation composition (shrub and herb layers) in Mt. Gyebang as a northern-temperate deciduous broadleaf forest. Tracheophytes were 146 taxa, consisting 56 families, 93 genera, 124 species, 17 varieties, 3 forma, 2 sub-species and 1 unknown taxa in research subject area. As species area curve analysis, herbaceous layer and shrub species have been decreased over time. As a result of Mantel-test, basal area of upper layer affects to understory vegetation change (p<0.0001). Mean importance value was dominated Lindera obtusiloba (21.585%), Rhododendron schlippenbachii (19.774%) in the shrub layer, identified Sasa borealis (14.082%) and Lindera obtusiloba (7.921%) in the herb layer. According to NMS analysis of shrub layer, Species characterized by strong correlation have been reduced as time goes by. And it reports different species as an increasing in basal area of the upper layer. Herb layer plots of the NMS analysis, Rhododendron schlippenbachii and Rhododendron mucronulatum consistently were affected in shrub layer. In consequence of MRPP-test for changes in vegetation composition, It was analyzed that there are no significant differences for vegetation composition changes on shrub layer in 5-10 years. As a changes of vegetation composition on herb layer were analyzed significantly, composition change of herb layer species was larger than shrub layer species in understory vegetation.

• Korean Journal of Soil Science and Fertilizer
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• v.40 no.4
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• pp.262-268
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• 2007

To characterize morphological classification of the basins, four major basin characteristics of the unit basins, including sinuosity, ratio of forest, ratio of flat area, and tributary existence were selected for cluster analysis. The analysis was carried out using soil map, topographic map, water course map, and basin map of the fifty unit basins in the Yeongsangang Basin. The unit basins could be categorized to five basin groups. The fitness by the Mantel test showed good fit of which r was 0.830. These grouping based on comprehensive soil and topographic characteristics provides best management practices, water quality management according to pollutants, increased water related model application and reasonable availability of water management. For agricultural management of water resources and conservation of water quality from agricultural non-point pollutants, therefore, comprehensive systematic classification of soil characteristics on unit basin might be an useful tool.

• Communications for Statistical Applications and Methods
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• v.14 no.3
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• pp.609-621
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• 2007

Diagnostic test results, which are approximately normal with a few number of outliers, but non-normal probability distribution, are frequently observed in practice. In the evaluation of two diagnostic tests, Greenhouse and Mantel (1950) proposed a parametric test under the assumption of normality but this test is inappropriate for the above non-normal case. In this paper, we propose a computationally simple nonparametric test that is based on quantile estimators of mean and standard deviation, instead of the moment-based mean and standard deviation as in some parametric tests. Parametric and nonparametric tests are compared with simulations under the assumption of, respectively, normality and non-normality, and under various combinations of the probability distributions for the normal and diseased groups.

• Environmental and Resource Economics Review
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• v.10 no.3
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• pp.387-412
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• 2001

This paper is to empirically test scope effects proposed to judge the internal consistency of contingent valuation method. The application was illustrated for the case of estimating people's WTP for improving water quality at Man Kyoung River in the Chon Buk area. The CV survey was carefully designed and implemented by carrying out recommendations from the NOAA Blue Ribbon panel. Using a split sample, we conducted the Cochran-Mantel-Haenszel test with the frequency distribution of no responses, calculated the Turnbull low bound mean for WTP, and measured the mean WTP from estimated variation functions. The test results consistently exhibited that the CV estimates of WTP were adequately responsive to the size of water quality changes being offered. The mean WTP for improving water quality suitable for swimming (5,171 and 5,212 won) was significantly larger than that for agricultural use and fishing activity (3,280 and 3,136 won).

• Journal of Korean Society of Forest Science
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• v.100 no.1
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• pp.34-41
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• 2011

Vegetation structure, composition and diversity were quantified for 10 samples ($10m{\times}10m$) representing woody vegetation and for 30 samples ($1m {\times}3m$) representing understory vegetation in Pinus parviflora and Tsuga sieboldii forest of Taeharyeong, Ulleung-gun (Gyeongsangbuk-do). P. parviflora was limitedly advanced to sapling layer from seedling stage, and based on Mantel tests, composition of canopy layer was not established in ground woody vegetation. Non-metric multidimensional scaling revealed influence of biotic and abiotic factors in species composition of woody and understory vegetation. In the result of multiple regression model, abundance of P. parviflora (density and breast height area) and percent cover of woody debris were significant predict variables for understory diversity. These results suggest that relatively large disturbance is required for regeneration of P. parviflora and T. sieboldii forest, and control of expansion of monocultural understory species that monopolize resources such as Carex blepharicarpa and Maianthemum dilatatum, is necessary for maintenance of diversity.

• The Korean Journal of Applied Statistics
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• v.21 no.1
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• pp.81-94
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• 2008

Family-based tests such as the transmission and disequilibrium tests(TDT) have proved to be powerful tools in the search for disease genes. Unlike case-control studies, the tests are not affected by population admixture, which can lead to spurious association of multiple highly linked makers with disease-susceptible genes. Those tests have largely required knowledge of parental marker genotypes. However, parental data are often not available for late-onset diseases. In this article we propose sib-TDTs that overcome this problem by use of marker data from unaffected sib(s) instead of parents. To do this end, we fist defined a Mantel-Haenszel-type statistic for each haplotype and then proposed two tests based on this statistic. Simulation studies suggest that the proposed tests are robust to population admixture and are monotone increasing as a relative risk increases irrespective of mode of inheritance. We also illustrated the proposed tests with data adopted from Yonsei Cardiovascular Genome Center.