• Title/Summary/Keyword: chi test

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Analysis of the Statistical Techniques and Errors in the Field of Sasang Constitution Researches: from 2011 to 2015 (최근 5년간(2011~2015) 사상체질분야 논문의 통계기법 분석 및 오류에 관한 연구)

  • Kim, Sujung;Kim, Sanghyuk;Lee, Siwoo
    • Journal of Sasang Constitutional Medicine
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    • v.28 no.1
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    • pp.51-56
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    • 2016
  • Objectives This study was to identify the types of errors in the statistical analysis and trends of previous reported papers that used various statistical techniques.Methods We have selected 118 original articles for statistical review from the OASIS(http://oasis.kiom.re.kr) and the Pubmed(http://www.pubmed.gov) in the field of Sasang constitutional medicine. Published year was restricted from 2011 to 2015.Results 1. The ANOVA(25.72%) was the statistic of choice overall, followed by the chi-square test(21.74%), regression analysis(14.13%), t-test(11.59%), and etc. 2. By examining the errors of the statistical methods, there were 42(59.2%) thesis with errors among 71 thesis using ANOVA, 19(31.7%) thesis among 60 thesis using chi-square test, and 35(89.7%) over 39 thesis using regression analysis.Conclusions To improve the quality of Sasang Constitution, the participation of statisticians in research design will reduce the significant errors in statistical interpretation of the results.

A Test for Randomness of the Binary Random Sequence (이진확률수열의 무작위성 검정)

  • Yeo, In-Kwon
    • The Korean Journal of Applied Statistics
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    • v.27 no.1
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    • pp.115-122
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    • 2014
  • A test for randomness of the binary random sequence is proposed in this paper. The proposed test statistic is based on the mean length of runs distributed with truncated geometric distribution and asymptotically ${\chi}^2_2$-distributed when the size of the sequences is large. A small Monte Carlo simulation compared the size of the test with a significant level as well as evaluated the test power. We applied the proposed method to the sequence of yes or no numbers in Lotto 6/45 and concluded that the randomness of Lotto is retained.

A Study on the Life Style in Clients with Colo-Rectal Cancer (대장암 환자의 생활양상에 관한 연구)

  • Kim, Mi-Suk;Jun, Jum-Yi;Son, Kyung-Hee
    • Korean Journal of Adult Nursing
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    • v.14 no.3
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    • pp.390-400
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    • 2002
  • Purpose: This study was to prepare the basic data for prevention of colorectal cancer and protection against its spread. Method: The subjects for the study were 204 patients with colorectal cancer from the G.S. wards of five general hospitals in Busan for the period of June 1 to September 1, 2001. The instrument used was a questionaire which was developed by Junho Shin(1995). The data was analyzed by descriptive statistics, McNemar test, ${\chi}^2$ test, paired t-test, and ANOVA. Result: 1. 57% of the studied subjects were male, 42.7% were more than 60 years old, 54.9% were of standard physique, 49.5% were the Buddhists, 50.5% were the middle or high school graduates, 83.8% were city dwellers, 48% were jobless, 69.6% had no-history of alimentary disease, 44.1% had no-family history of cancer, 82.8% were married. 2. Constipation (${\chi}^2=36.45$, p=0.0001) in clients showed a significant positive association for the prediagnosed, but diarrhea(${\chi}^2=3.947$, p=0.047) showed a significant positive association for the post-diagnosed. The preference for high seasonings(t=6.23, p=0.0001) and animal fat (t=8.35, p=0.0001) was higher significantly in the pre-diagnosed, but physical activities(${\chi}^2=30.22$, p=0.0001), an eutrophic or tonic medicine(${\chi}^2=30.22$, p=0.0001), was of and vegetables(t=-6.20, p=0.0001) was higher significantly in the post-diagnosed. 3. There were significant differences in the life style of the pre-diagnosed according to the general characteristics except religion. Conclusion: Results of the above study reveal we should be very sensitive to the change of defecation styles and consider the necessity of improving life styles as regards eating habits. When an education program is developed, the general characteristics of the subjects need to be considered.

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On an Approximation to the Distribution of Product of Independent Beta Variates

  • Hea Jung Kim
    • Communications for Statistical Applications and Methods
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    • v.1 no.1
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    • pp.81-86
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    • 1994
  • A Chi-square approximation to the distribution of product of independent Beta variates denoted by U is developed. The distribution is commonly used as a test criterion for the general linear hypothesis about the multivariate linear models. The approximation is obtained by fitting a logarithmic function of U to a Chi-square variate in terms of the first three moments. It is compared with the well known approximations due to Box(1949), Rao(1948), and Mudholkar and Trivedi(1980). It is found that the Chi-square approximation compares favorably with the other three approximations.

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Error cause analysis of Pearson test statistics for k-population homogeneity test (k-모집단 동질성검정에서 피어슨검정의 오차성분 분석에 관한 연구)

  • Heo, Sunyeong
    • Journal of the Korean Data and Information Science Society
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    • v.24 no.4
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    • pp.815-824
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    • 2013
  • Traditional Pearson chi-squared test is not appropriate for the data collected by the complex sample design. When one uses the traditional Pearson chi-squared test to the complex sample categorical data, it may give wrong test results, and the error may occur not only due to the biased variance estimators but also due to the biased point estimators of cell proportions. In this study, the design based consistent Wald test statistics was derived for k-population homogeneity test, and the traditional Pearson chi-squared test statistics was partitioned into three parts according to the causes of error; the error due to the bias of variance estimator, the error due to the bias of cell proportion estimator, and the unseparated error due to the both bias of variance estimator and bias of cell proportion estimator. An analysis was conducted for empirical results of the relative size of each error component to the Pearson chi-squared test statistics. The second year data from the fourth Korean national health and nutrition examination survey (KNHANES, IV-2) was used for the analysis. The empirical results show that the relative size of error from the bias of variance estimator was relatively larger than the size of error from the bias of cell proportion estimator, but its degrees were different variable by variable.

Studies on the Adherence and Corrosion Resistance of Oxide Coated Materials ( 1 ) (산화물 피복강재의 밀착성과 내식성에 관한 연구 ( 1 ))

  • Lee, Jong-Rark;Lim, U-Joh
    • Journal of the Korean Society of Fisheries and Ocean Technology
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    • v.32 no.2
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    • pp.157-163
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    • 1996
  • To ceramic film, $SiO_2$ and $Al_2O_3$, coated on pure Fe and stainless steel(SUS41O) by RF magnetron sputtering, the adherence between mm and substarte was studied. The adherence index (${\chi}$) was determined by the measure of micro hardness test. Also, the corrosion resistance on oxide coatings was studied using electrochemical measurement. The main results obtained are as the following: 1) In the micro-hardness test, with $1{\mu}m$ thickness mm, it has only one the value of ${\chi}$. Above $2{\mu}$thickness fIlm, however, get another value of ${\chi}$as the cracks in fIlm. 2) The oxide fIlm adhere well on the mild materials such as pure steel than high intensity materials like stainless. 3) Alumina($Al_2O_3$) coated materials have better corrosion resistance than silica($SiO_2$)coated materials

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Effect of Aging Time on the Resistance to Localized Corrosion of the Hyper Duplex Stainless Steel

  • Jeon, Soon-Hyeok;Kim, Soon-Tae;Lee, In-Sung;Kim, Ji-Soo;Kim, Kwang-Tae;Park, Yong-Soo
    • Corrosion Science and Technology
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    • v.9 no.5
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    • pp.209-215
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    • 2010
  • To elucidate the effect of aging time on resistance to localized corrosion of hyper duplex stainless steel, a double-loop electrochemical potentiokinetic reactivation test a potentiodynamic anodic polarization test, a scanning electron microscope-energy dispersive spectroscope analysis, and a thermodynamic calculation were conducted. With an increase in aging time, sigma phases are precipitated much more than chi phases due to the meta-stable chi phase acting as a transition phase. As aging time at $850^{\circ}C$ increases, the corrosion resistance decreases owing to an increase in Cr, Mo and W depleted areas adjacent to the intermetallic phases such as sigma phases and chi phases.

Mining Positive and Negative Association Rules Algorithm based on Correlation and Chi-squared analysis (상관관계와 카이-제곱 분석에 기반한 긍정과 부정 연관 규칙 알고리즘)

  • Kim, Na-hee;Youn, Sung-dae
    • Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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    • 2009.10a
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    • pp.223-226
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    • 2009
  • Recently, Mining negative association rules has received some attention and proved to be useful. Negative association rules are useful in market-basket analysis to identify products that conflict with each other or products that complement each other. Several algorithms have been proposed. However, there are some questions with those algorithms, for example, misleading rules will occur when the positive and negative rules are mined simultaneously. The chi-squared test that based on the mature theory and Correlation Coefficient can avoid the problem. In this paper, We proposed the algorithm PNCCR based on chi-squared test and correlation is proposed. The experiment results show that the misleading rules are pruned. It suggests that the algorithm is correct and efficient.

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Determination of 3-D Positions on TBMs Using the Precise GPS Data analysis SW, GAMIT/GLOBK (정밀 GPS 해석 S/W GMAIT/GLOBK를 활용한 TBM의 3차원 위치 결정)

  • Yoo, Kyung-Wan;Yang, In-Tae;Lee, Dong-Ha
    • Journal of Industrial Technology
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    • v.36
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    • pp.71-76
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    • 2016
  • In this study, we determined the precise coordinates of TBMs (Tidal Bench Marks), which used as the national reference points in coastal area of Korea, using a GPS data analysis SW for the academic and scientific applications, GAMIT/GLOBK. For accurate 3-D positioning of TBM locations, we performed the GPS point surveying according to the national surveying policy and also acquired the GPS data for 48 TBMs located in the western and southern coastal part of Korea. Considering the results of baseline analysis to each observation session obtained from GAMIT module, the baseline analysis was realized to be done precisely because the values of Normalized RMS (NRMS) were mostly less than ${\pm}0.20mm$. Before the network adjustment using GLOBK module, we evaluated the suitability of observations for each session by applying the chi-squared test (${\chi}^2$ test) to the degree of freedom in observed session. An overall distributions of ${\chi}^2$ test were less than 1.0 for all sessions, and the statistical of ${\chi}^2$ test showed the average, 0.267 with minimum and maximum value, 0.063 and 0.653, respectively. Finally, we analyzed the network adjustment for 48 TBMs to reduce the residuals of baseline analysis on each point by connecting with 42 permanent GPS stations in Korea. In the network adjustment procedure, we set up the weighted values of each permanent station to be allocated between 0.9 and 1.14, and also removed the observed points having residual exceeds 4-times of standard deviation ($4{\sigma}$).

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Video Segmentation using the Automated Threshold Decision Algorithm (비디오 분할을 위한 자동 임계치 결정 알고리즘)

  • Ko Kyong-Cheol;Lee Yang-Won
    • Journal of the Korea Society of Computer and Information
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    • v.10 no.6 s.38
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    • pp.65-74
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    • 2005
  • This Paper Propose a robust scene change detection technique that use the weighted chi-square test and the automated threshold-decision algorithm. The weighted chi-test can subdivide the difference values of individual color channels by calculating the color intensities according to mSC standard, and it can detect the scene change by joining the weighted color intensities to the predefined chi-test which emphasize the comparative color difference values. The automated decision algorithm uses the difference values of frame-to-frame that was obtained by the weighted chi-test. In the first step, The average of total difference value and standard deviation value is calculated and then, subtract the mean value from the each difference values. In the next step, the same process is performed on the remained difference value. The propose method is tested on various sources and in the experimental results, it is shown that the Proposed method is efficiently estimates the thresholds and reliably detects scene changes.

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