• Title, Summary, Keyword: 추세검정

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A Composite Trend Test with Symptom Occurrence and Severity Symptom Scores (증상 발현과 증상 심각성을 병합한 추세검정법)

  • Choi, Se-Mi;Yang, Soo;Song, Hae-Hiang
    • The Korean Journal of Applied Statistics
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    • v.24 no.6
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    • pp.1045-1054
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    • 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.

Trend Test of the Mean and Extreme Sea Level Data in the Korean Coast (우리나라 연안의 평균해면 및 최극조위 자료의 추세 검정)

  • Kang, Ju-Whan;Cho, Hong-Yeon;Park, Min-Won;Park, Seon-Jung
    • Proceedings of the Korea Water Resources Association Conference
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    • pp.2156-2160
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    • 2008
  • 우리나라 연안의 평균해면이 증가하고 있다는 주장과 고극조위, 저극조위가 증가(또는 변동)하고 있다는 주장이 제기되고 있으나, 연구자가 사용한 자료의 기간 및 분석 방법 등에 차이가 있고, 결측자료(missing data) 및 이상자료(outlier) 등을 처리한 방법이 서로 차이가 있기 때문에 전체적으로 또는 부분적으로 분석결과가 차이를 보일 수 있다. 또한 추세분석에서는 통계적인 신뢰수준에 대한 검정과정 없이 단순하게 선형회귀곡선식을 이용하여 기울기의 부호만으로 증가 감소를 판단하는 경우도 있다. 그러나 추세분석은 최적의 추세곡선을 찾아내는 것 이전에 추세의 유무를 통계적인 신뢰수준을 기준으로 검정하는 것이 필요하다. 본 연구에서는 추세분석의 필수과정인 추세검정(추세가 있는가? 없는가?)을 Mann-Kendall 방법을 이용하여 우리나라 전 연안 조위관측소의 평균해수면 및 고극조위, 저극조위 자료에 대하여 수행하였다. 추세검정 결과를 다음과 같이 도출할 수 있었다. 평균해수면은 95% 유의수준으로 분석에 포함된 전체 30개 검조소 중 대산, 보령, 군산, 목포, 통영, 거문도, 부산, 가덕도, 제주, 서귀포, 속초, 포항, 울산, 울릉도 지점 등 19개 지점이 추세가 있는 것으로 파악되었으며, 고극조위, 저극조위는 각각 15개, 17개 지점이 추세가 있는 것으로 파악되었다.

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Characterization of Long-term Trends of Rainfall and Stream Flow in South Korea (한반도 강수량과 유량의 장기 추세 분석)

  • Kim, Gwang-Seob;Yim, Tae-Kyung
    • Proceedings of the Korea Water Resources Association Conference
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    • pp.916-919
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    • 2005
  • 기후변화에 따른 강수변화특성 연구는 장기 강수의 추세변화가 가용수자원과 관련된 여러 문제들과 밀접하게 연관되어 있기 때문에 중요하다. Mann-Kendall 검정을 사용하여 한반도의 월별 및 년 강수량과 유량의 추세검증분석을 수행하였다. 한반도 강우특성의 장기추세는 총강우량 증가, 총 강우일수 감소 그리고 80mm 이상 강우일수 증가로 요약될 수 있다. 강수자료의 추세분석에서는 강수량의 증가와 강우일수의 감소 그리고 호우일수의 증가를 볼 수 있었지만 MK 검정결과 $90\%$$95\%$ 유의성을 가진 증가나 감소의 추세성을 보이지는 않았다. 이는 강수량의 증가로 인한 유량의 증가 추세가 유량자체의 변동 특성보다 크지 않으므로 유량자료의 추세에서 통계적 유의성을 가지는 어떠한 경향성을 찾을 수 없음을 나타낸다.

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A Nonparametric Stratified Test Based on the Jonckheere-Terpstra Trend Statistic (Jonckheere-Terpstra 추세 검정통계량에 근거한 비모수적 층화분석법)

  • Cho, Do-Yeon;Yang, Soo;Song, Hae-Hiang
    • The Korean Journal of Applied Statistics
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    • v.23 no.6
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    • pp.1081-1091
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    • 2010
  • Clinical trials are often carried out as multi-center studies because the patients enrolled for a trial study are very limited in one particular hospital. In these circumstances, the use of an ordinary Jonckheere (1954) and Terpstra (1952) test for testing trend among several independent treatment groups is invalid. We propose a the stratified Jonckheere-Terpstra test based on van Elteren (1960)'s stratified test of Wilcoxon (1945) statistics and an application of our method is demonstrated through example data. A simulation study compares the efficiency of stratified and unstratified Jonckheere-Terpstra trend tests.

Comparison of Trend Tests for Genetic Association with Sibship Data (형제 자료에 근거한 유전연관성 추세 검정법의 비교)

  • Oh, Young-Sin;Kim, Han-Sang;Son, Hae-Hiang
    • The Korean Journal of Applied Statistics
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    • v.23 no.5
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    • pp.845-855
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    • 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.

Comparison of Trend Tests for Genetic Association on Censored Ages of Onset (미완결 발병연령에 근거한 연관성 추세 검정법의 비교)

  • Yoon, Hye-Kyoung;Song, Hae-Hiang
    • The Korean Journal of Applied Statistics
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    • v.21 no.6
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    • pp.933-945
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    • 2008
  • The genetic association test on age of onset trait aims to detect the putative gene by means of linear rank tests for a significant trend of onset distributions with genotypes. However, due to the selective sampling of recruiting subjects with ages less than a pre-specified limit, the genotype groups are subject to substantially different censored distributions and thus this is one reason for the low efficiencies in the linear rank tests. In testing the equality of two survival distributions, log-rank statistic is preferred to the Wilcoxon statistic, when censored observations are nonignorable. Therefore, for more then two groups, we propose a generalized log-rank test for trend as a genetic association test. Monte Carlo studies are conducted to investigate the performances of the test statistics examined in this paper.

Comparison of Principal Component Regression and Nonparametric Multivariate Trend Test for Multivariate Linkage (다변량 형질의 유전연관성에 대한 주성분을 이용한 회귀방법와 다변량 비모수 추세검정법의 비교)

  • Kim, Su-Young;Song, Hae-Hiang
    • The Korean Journal of Applied Statistics
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    • v.21 no.1
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    • pp.19-33
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    • 2008
  • Linear regression method, proposed by Haseman and Elston(1972), for detecting linkage to a quantitative trait of sib pairs is a linkage testing method for a single locus and a single trait. However, multivariate methods for detecting linkage are needed, when information from each of several traits that are affected by the same major gene are available on each individual. Amos et al. (1990) extended the regression method of Haseman and Elston(1972) to incorporate observations of two or more traits by estimating the principal component linear function that results in the strongest correlation between the squared pair differences in the trait measurements and identity by descent at a marker locus. But, it is impossible to control the probability of type I errors with this method at present, since the exact distribution of the statistic that they use is yet unknown. In this paper, we propose a multivariate nonparametric trend test for detecting linkage to multiple traits. We compared with a simulation study the efficiencies of multivariate nonparametric trend test with those of the method developed by Amos et al. (1990) for quantitative traits data. For multivariate nonparametric trend test, the results of the simulation study reveal that the Type I error rates are close to the predetermined significance levels, and have in general high powers.

The Study for Comparative Analysis of Software Failure Time Using EWMA Control Chart (지수 가중 이동 평균 관리도를 이용한 소프트웨어 고장 시간 비교분석에 관한 연구)

  • Kim, Hee-Cheul;Shin, Hyun-Cheul
    • Convergence Security Journal
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    • v.8 no.3
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    • pp.33-39
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    • 2008
  • Software failure time presented in the literature exhibit either constant, monotonic increasing or monotonic decreasing. For data analysis of software reliability model, data scale tools of trend analysis are developed. The methods of trend analysis are arithmetic mean test and Laplace trend test. Trend analysis only offer information of outline content. In this paper, we discuss exponentially weighted moving average chart, in measuring failure time. In control, exponentially weighted moving average chart's uses are efficiency case of analysis with knowing information, Using real software failure time, we are proposed to use exponentially weighted moving average chart and comparative analysis of software failure time.

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Locally Powerful Unit-Root Test (국소적 강력 단위근 검정)

  • Choi, Bo-Seung;Woo, Jin-Uk;Park, You-Sung
    • Communications for Statistical Applications and Methods
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    • v.15 no.4
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    • pp.531-542
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    • 2008
  • The unit root test is the major tool for determining whether we use differencing or detrending to eliminate the trend from time series data. Dickey-Fuller test (Dickey and Fuller, 1979) has the low power of test when the sample size is small or the true coefficient of AR(1) process is almost unit root and the Bayesian unit root test has complicated testing procedure. We propose a new unit root testing procedure, which mixed Bayesian approach with the traditional testing procedure. Using simulation studies, our approach showed locally higher powers than Dickey-Fuller test when the sample size is small or the time series has almost unit root and simpler procedure than Bayesian unit root test procedure. Proposed testing procedure can be applied to the time series data that are not observed as process with unit root.

The Study for Software Future Forecasting Failure Time Using Time Series Analysis. (시계열 분석을 이용한 소프트웨어 미래 고장 시간 예측에 관한 연구)

  • Kim, Hee-Cheul;Shin, Hyun-Cheul
    • Convergence Security Journal
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    • v.11 no.3
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    • pp.19-24
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    • 2011
  • Software failure time presented in the literature exhibit either constant monotonic increasing or monotonic decreasing, For data analysis of software reliability model, data scale tools of trend analysis are developed. The methods of trend analysis are arithmetic mean test and Laplace trend test. Trend analysis only offer information of outline content. In this paper, we discuss forecasting failure time case of failure time censoring. In this study, time series analys is used in the simple moving average and weighted moving averages, exponential smoothing method for predict the future failure times, Empirical analysis used interval failure time for the prediction of this model. Model selection using the mean square error was presented for effective comparison.