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

• Communications for Statistical Applications and Methods
• /
• v.15 no.3
• /
• pp.403-409
• /
• 2008

In this paper we show that the peak of the type I error rate of the Oochran-Armitage trend test could be greater than the nominal level when $2\;{\times}\;C$ contingency tables obtained from two multinomial distributions are extremely unbalanced. This result justifies the use of the exact Cochran-Armitage trend test in extremely unbalanced $2\;{\times}\;C$ contingency tables.

• Journal of the Korean Data and Information Science Society
• /
• v.23 no.4
• /
• pp.657-663
• /
• 2012

There are very small values and/or very big values which get out of the normal range for survey data in various fields. The reasons of occurrence for outlier are two. One of them is the error in process of data input and the other is the strange response of the respondent. If the data has outliers, then the summary statistics such as the mean and the variance produce misleading information. Therefore, researcher should be careful in detecting the outlier in data. In particular, it is very important problem for clinical fields because the cost of experiment is very high. This article introduce the Grubb test and Cochran test to detect outliers in the data and we apply this method for clinical data.

• The Korean Journal of Applied Statistics
• /
• v.23 no.5
• /
• pp.845-855
• /
• 2010

Extensively used case-control designs in medical studies can also be powerful and efficient for family association studies as long as an analysis method is developed for the evaluation of association between candidate genes and disease. Traditional Cochran-Armitage trend test is devised for independent subjects data, and to apply this trend test to the biologically related siblings one has to take into account the covariance among related family members in order to maintain the correct type I error rate. We propose a more powerful trend test by introducing weights that reflect the number of affected siblings in families for the evaluation of the association of genetic markers related to the disease. An application of our method to a sample family data, in addition to a small-scale simulation, is presented to compare the weighted and unweighted trend tests.

• The Korean Journal of Applied Statistics
• /
• v.24 no.6
• /
• pp.1045-1054
• /
• 2011

During clinical trials a researcher is frequently able to observe a disease symptom in a subject as well as a severity score for those who experienced a symptom after a fixed length of treatment. The traditional method to evaluate a decreasing trend in proportion, when there is an intrinsic order in the treatment groups (for example control and two or more treatment groups) is a Cochran-Armitage test, while the method to evaluate a decreasing trend in continuous non-normal data is a Jonckheere-Tersptra test. The Cochran-Armitage test emphasizes the dichotomous data of symptom occurrence and the Jonckheere-Tersptra test emphasizes the continuous non-normal data of severity symptom scores. In this paper we propose new test statistics that consider the combined evidence from a symptom occurrence and disease severity score. We illustrate these methods with example data of schizophrenic inpatients that demonstrated antipsychotic-drug induced constipation. A small-scale simulation is conducted to compare the new trend tests with other trend tests.

• Communications for Statistical Applications and Methods
• /
• v.24 no.6
• /
• pp.663-671
• /
• 2017

Some genetic association tests include an unidentifiable nuisance parameter under the null hypothesis of no association. When the mode of inheritance (MOI) is not specified in a case-control design, the Cochran-Armitage (CA) trend test contains an unidentifiable nuisance parameter. The transmission disequilibrium test (TDT) in a family-based association study that includes the unaffected also contains an unidentifiable nuisance parameter. The hypothesis tests that include an unidentifiable nuisance parameter are typically performed by taking a supremum of the CA tests or TDT over reasonable values of the parameter. The p-values of the supremum test statistics cannot be obtained by a normal or chi-square distribution. A common method is to use a Davies's upper bound of the p-value instead of an exact asymptotic p-value. In this paper, we provide a unified sine-cosine process expression of the CA trend test that does not specify the MOI and the TDT that includes the unaffected. We also present a closed form expression of the exact asymptotic formulas to calculate the p-values of the supremum tests when the score function can be written as a linear form in an unidentifiable parameter. We illustrate how to use the derived formulas using a pharmacogenetics case-control dataset and an attention deficit hyperactivity disorder family-based example.

• Journal of the Korea Concrete Institute
• /
• v.27 no.6
• /
• pp.695-703
• /
• 2015

Acceptance criteria for chemical admixtures of cement concrete were investigated in domestic and international specifications. The reliability was verified for solid content test method of chemical admixture examined statistical analysis by round robin test. The applicability of FT-IR spectroscopy for qualitative measurement of multi-compound chemical admixtures verified. From solid content experimental results, outlier analysed using Cochran, Grubbs and Dickson's Q test. Repeatability and reproducibility standard deviation for solid content results showed 0.25 and 0.098% respectively according to KS A ISO 5725-2 procedure, it can be confirmed reliability of test methods. FT-IR spectrum of liquefied or oven-dried chemical admixtures condition showed big differences. It is needed that the FT-IR analysis is performed on dry material. However there's no difference with the applicability of FT-IR spectroscopy for multi-compound chemical admixtures. So the utility of method analysis could not identify.

• Journal of the Korean Society for Precision Engineering
• /
• v.27 no.4
• /
• pp.40-45
• /
• 2010

Evaluation of uncertainty is an ongoing process that can consume time and resources. It can also require the service of someone who is familiar with data analysis techniques. Therefore, it is important for laboratory personnel who are approaching uncertainty analysis for the first time to be aware of the resources required. International inclination of measurement filed to guarantee the traceability and confidence of measurement results discards the error concept and instead analyzes the measurement uncertainty. In this paper, we analyzed the elements of measurement uncertainty on surface roughness test which are the important things in mechanical parts test. Repeat the test by 3 men, the measurement uncertainty could be calculated.

• Environmental and Resource Economics Review
• /
• v.10 no.3
• /
• pp.387-412
• /
• 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 the Korea Institute of Military Science and Technology
• /
• v.6 no.3
• /
• pp.62-73
• /
• 2003

The characteristics of constitutive equations, for hydrocodes, were Investigated by the comparison between the smoothed particle hydrodynamcis simulation and the experiment of rod impact test which resulted in a deformation history of impacting front where high strain and high strain rate dominate. The constitutive equations used in the simulation Is J-C(Johnson-Cook) model, Z-A(Zerilli-Armstrong) model, and S-C-G(Steinberg-Cochran-Guinan) model. The modification of Z-A model, based on the increased effect of strain-rate hardening, showed better correlation with expriment.