• Title/Summary/Keyword: chi-square test

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Equivocal Association of RAD51 Polymorphisms with Risk of Esophageal Squamous Cell Carcinoma in a Chinese Population

  • Zhang, Shu-Xiang;Yang, Shan;Xu, Chang-Qing;Hou, Rui-Ping;Zhang, Chuan-Zhen;Xu, Cui-Ping
    • Asian Pacific Journal of Cancer Prevention
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    • v.15 no.2
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    • pp.763-767
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    • 2014
  • Aim: To study the contribution of genetic variation in RAD51 to risk of esophageal squamous cell carcinoma (ESCC). Methods: Three single nucleotide polymorphisms (SNPs) in RAD51 (rs1801320, rs4144242 and rs4417527) were genotyped in 316 ESCC patients and 316 healthy controls in Anyang area of China using PCR-RFLP (polymerase chain reaction-restriction fragment length polymorphism). Demographic variables between cases and controls were statistically compared by T test and Chi-square test. Hardy-Weinberg equilibrium was evaluated by the Chi-square test. Odds ratios (ORs) and 95% confidence intervals (CIs) were calculated to measure any association with ESCC. Haplotype frequencies were estimated by Phase 2.1. Result: The genotype frequencies of rs1801320, rs4144242 and rs4417527 in patients with ESCC demonstrated no significant differences from those in control group (P>0.05). When the haplotypes of these three SNPs were constructed and their relationships with ESCC risk investigated, however, CGG was observed to increase the risk (P=0.020, OR=2.289). Conclusions: There was no association between the three SNPs of RAD51 and ESCC susceptibility in our Chinese population. However, the CGG haplotype might be a risk factor.

Correlation between personal temperament, dental visit, and dental fear among adults (일부 성인의 개인적 기질 및 치과 방문경험과 치과공포와의 상관성)

  • Kim, Chul-Sin;Choi, Yong-Keum
    • Journal of Korean society of Dental Hygiene
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    • v.16 no.6
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    • pp.1057-1066
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    • 2016
  • Objectives: The purpose of the study was to investigate the correlation between personal temperament, dental visit, and dental fear among adults. Methods: A self-reported questionnaire was completed by 400 adults visiting dental clinics from April to June, 2016. The questionnaire consisted of general characteristics of the subjects, dental fear, and temperament. Data were analyzed by t test, chi-square test, chi-square test, and pearson's correlation analysis using SPSS v. 23.0. Results: The first impression of dental clinics had an impact on dental fear (p<0.001). The negative image on the dental clinics increased dental fear of the visitors. There was a significant difference between the purpose of dental visit and dentla fear. Conclusions: The positive image of the dental clinics can solve the dental fear due to treatment in the adults. The dental consumers should try to have the comfortable attitude toward dental clinic in case of visit.

Investigation of swine toxoplasmosis by Latex agglutination and polymerase chain reaction(PCR) (Latex 응집반응 및 polymerase chain reaction을 이용한 돼지톡소플라즈마병 감염실태 조사)

  • Shim, Hang-Sub;Choi, Gyeong-Muk;Jeon, Oh-Sook;Lee, Su-Jin;Woo, Jong-Tae;Ro, Ki-Woan
    • Korean Journal of Veterinary Service
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    • v.31 no.1
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    • pp.87-91
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    • 2008
  • Between March and October 2007, a total of 516 blood samples from pigs in the Gyeonggi province were examined for seroprevalence against toxoplasmosis by latex agglutination test (LAT) and the detection of antigenic particles among seropositive samples by PCR. In the LAT, 118 (22.8%) were positive, and the unadjusted percentage of seroprevalence rates of breeding and fattening pigs were significant difference. Positive rate (14.1%) in the breeding pigs was much lower than that (27.8%) of the fattening pigs (p<0.001, Pearson's Chi-square test). The antibody detection rate of sows was lower than fattening pigs, i.e., 15.8% (25/158) and 26% (93/358), respectively (P=0.011, Pearson's Chi-square test). Among 118 seropositive samples by LAT, 68 (57.6%) were positive in PCR for the detection of the toxoplasma specific-DNA. There was a statistical difference in the positive PCR reaction between the raising pigs(63/93 67.7%) and sows (5/25, 20%) (P<0.01).

Probability Distribution Model of Received W-CDMA Signals in the Realistic Wideband Multipath Channel (광대역 다중경로 실측채널에서 W-CDMA 수신 신호의 확률분포 모델)

  • 오동진;이주석;장근영;김철성
    • Proceedings of the IEEK Conference
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    • 2000.06a
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    • pp.197-200
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    • 2000
  • This paper presents a mathematical model of the output of Rake receiver of W-CDMA signals for various outdoor channel environment and different bandwidths. This mathematical model is represented as Rayleigh and noncentral chi distribution with 3 degrees of freedom. Those are obtained from the statistics of numerically generated signals. We employ Chi-square test to show how the mathematical model fits signal statistics, and confirmed that this model is appropriate for representing W-CDMA signals.

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The Influence of Maximal Aerobic Capacity on the Two Years Cardiac Related Re-Hospitalization in Patients with Heart Failure with Reduced Ejection Fraction in Korean Society

  • Ryu, Ho Youl;Hong, Do Sun;Kim, Tack Hoon
    • The Journal of Korean Physical Therapy
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    • v.31 no.5
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    • pp.322-327
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    • 2019
  • Purpose: This study examined the influence of the maximal aerobic capacity on the two-year cardiac-related re-hospitalization in patients with heart failure with a reduced ejection fraction (HFrEF) in Korean society. Methods: The maximal aerobic capacity of the study population (n=95, male 63%) was evaluated using a cardiopulmonary exercise (CPX) testing system. Each patient was followed up for two years to divide the HFrEF patients into two groups according to cardiac-related re-hospitalization: re-hospitalization (RH) group (n=29, 30%) and no re-hospitalization (NRH) group (n=66, 70%). Results: The relative peak $VO_2$ (mL/kg/min, p<0.001), exercise duration (p<0.001), respiratory exchange ratio ($VCO_2/VO_2$, p=0.001), systolic blood pressure (SBP) reserve (p=0.004), heart rate (HR) reserve (p=0.007), SBP max (p=0.02), and HR max (p=0.039) were significantly lower in the RH group than the NRH group during the CPX test. On the other hand, the ventilatory efficiency (VE/VCO2 slope, p=0.02) and age (p=0.022) were significantly higher in the RH group than in the NRH group. In binary logistic regression analysis, the relative peak $VO_2$ (p=0.001, Wald Chi-square 10.137) was the strongest predictive factor on cardiac-related re-hospitalization, which was followed by $VCO_2/VO_2$ (p=0.019, Wald Chi-square 5.54). On the other hand, age (p=0.063, Wald Chi-square 3.445) did not have a significant influence on cardiac related re-hospitalization. Conclusion: The maximal aerobic capacity, especially the relative peak $VO_2$, is the strongest factor on cardiac-related re-hospitalization within two years in patients with HFrEF in Korean society.

Ljung-Box Test in Unit Root AR-ARCH Model

  • Kim, Eunhee;Ha, Jeongcheol;Jeon, Youngsook;Lee, Sangyeol
    • Communications for Statistical Applications and Methods
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    • v.11 no.2
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    • pp.323-327
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    • 2004
  • In this paper, we investigate the limiting distribution of the Ljung-Box test statistic in the unit root AR models with ARCH errors. We show that the limiting distribution is approximately chi-square distribution with the degrees of freedom only depending on the number of autocorrelation lags appearing in the test. Some simulation results are provided for illustration.

Non-Conservatism of Bonferroni-Adjusted Test

  • Jeon, Cyeong-Bae;Lee, Sung-Duck
    • Communications for Statistical Applications and Methods
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    • v.8 no.1
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    • pp.219-227
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    • 2001
  • Another approach (multi-parameter measurement method) of interlaboratory studies of test methods is presented. When the unrestricted normal likelihood for the fixed latent variable model is unbounded, we propose a me쇙 of restricting the parameter space by formulating realistic alternative hypothesis under which the likelihood is bounded. A simulation study verified the claim of conservatism of level of significance based on assumptions about central chi-square distributed test statistics and on Bonferroni approximations. We showed a randomization approach that furnished empirical significance levels would be better than a Bonferroni adjustment.

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A Study on Cell Influences to Chi-square Statistic in Contingency Tables

  • Kim, Hong-Gie
    • Communications for Statistical Applications and Methods
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    • v.5 no.1
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    • pp.35-42
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    • 1998
  • Once a contingency table is constructed, the first interest will be the hypotheses of either homogeneity or independence depending on the sampling scheme. The most widely used test statistic in practice is the classical Pearson's $\chi^2$ statistic. When the null hypothesis is rejected, another natural interest becomes which cell contributed to the rejection of the null hypothesis more than others. For this purpose, so called cell $\chi^2$ components are investigated. In this paper, the influence function of a cell to the $\chi^2$ statistic is derived, which can be used for the same purpose. This function measures the effect of each cell to the $\chi$$^2$ statistic. A numerical example is given to demonstrate the role of the new function.

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The Comparison of Variables between Therapy Continuity Group and Therapy Discontinuity Group of Patients With Hypertension and Diabetes in Daegu Initiative (심뇌혈관질환 고위험군 중 치료연속자와 치료불연속자 간의 특성 비교)

  • Park, Jeong-Sook;Kwon, Young-Sook;Oh, Yun-Jung
    • Korean Journal of Health Education and Promotion
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    • v.26 no.2
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    • pp.135-148
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    • 2009
  • Objectives: The purpose of this study is to identify the characteristics between therapy continuity group and therapy discontinuity group and to develop management program for Korean patients with hypertension and diabetes. Methods: The subject of the study were 109 therapy continuity and 66 therapy discontinuity of Korea hypertension diabetes Daegu initiative. The data collection was performed from December 5 to December 30, 2008. Analysis of data was done by using descriptive statistics, chi-square test, t-test and ANCOVA with SPSS program. Results: 1) The groups were significantly correlated with such variables systolic BP(F=4.518, p=0.035) and diastolic BP(F=17.793, p=0.000). 2) The groups with hypertensive were significantly correlated with such variables perceived susceptibility of disease($\chi^2$=25.053, p=0.000), perceived barrier of health behavior($\chi^2$=12.584, p=0.006), drinking($\chi^2$=27.545, p=0.000), diet($\chi^2$=8.645, p=0.013), regular taking medicine($\chi^2$=92.415, p=0.000) and regular measurement of BP($\chi^2$=6.045, p=0.049). 3) The groups with diabetic were significantly correlated with such variables perceived seriousness of disease($\chi^2$=6.128, p=0.047), perceived susceptibility of disease($\chi^2$=8.079, p=0.018), health knowledge and attitude(F=8.418, p=0.006), drinking($\chi^2$=6.276, p=0.043), diet($\chi^2$=7.275, p=0.026), regular taking medicine($\chi^2$=33.083, p=0.000) and regular measurement of glucose($\chi^2$=7.233, p=0.027). Conclusion: The above findings indicate that it is necessary to develop and apply special management programs according to the therapy discontinuity group.

Analysis of Bird Community by Habitat Type in Nak-dong Jeongmaek (낙동정맥의서식지유형별조류군집분석)

  • Han, Seung-Woo;Kang, Te-han;Park, Chi-Young;Shin, Yong-Un;Im, Eun-Hong;Lee, Joon-Woo
    • Korean Journal of Environment and Ecology
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    • v.30 no.3
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    • pp.335-343
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    • 2016
  • Of the Nak-dong Jeongmaek, five mountains, viz. Mt. Baek-byeong, Mt. Chil-bo, Mt. Baek-am, Mt. Un-ju, Mt. Go-heon, which are considered to well represent the natural environmental characteristics of Nak-dong Jeongmaek as well as its various terrain, were selected for this study. Two fixed plots were selected as sample study areas of each type of bird habitats and surveyed from May to October in 2015. According to the results of the survey conducted in the five mountains of Nak-dong Jeongmaek, a total of 47 species with 1,163 individuals birds was identified. The largest variety of species occupying a particular habitat type was found in the forest road and the ridge with 31 species. Also, the number of individuals was highest in the valley with 471 individuals. According to the results of nesting guild analysis of the vein (Pearson Chi-Square test, ${\chi}^2=13.377$, p = 0.037) by each Nak-dong Jeongmaek habitat type, the communities that belong to the canopy nesting guild showed a high frequency in development land and the valley while the communities that belong to the hole nesting guild showed a high frequency on the forest road and ridge. The results of Pearson Chi-Square test (${\chi}^2=15.555$, p=0.004) showed that the communities that belong to Bush foraging guild were most frequent in the development area and the community that belong to canopy foraging guild were most frequent inthe valley, the forest road and the ridge. These findings show that different habitat types of Nak-dong Jeongmaek support a great variety of birdlife by providing diverse and excellent resources.