• Title/Summary/Keyword: ${\chi}^2$-test

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Testing for Failure Rate Ordering between Survival Distributions

  • Park, Chul-Gyu
    • Journal of the Korean Statistical Society
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    • v.23 no.2
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    • pp.349-365
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    • 1994
  • We develop in this paper the likelihood ratio test (LRT) for testing $H_1 : F_1 \preceq F_2$ against $H_2 - H_1$ where $H_2$ imposes no restriction on $F_1$ and $F_2$ and '$\preceq$' means failure rate ordering. Both one and two-sample problems will be considered. In the one-sample case, one of the two distributions is known, while we assume in the other case both are unknown. We derive the asymptotic null distribution of the LRT statistic which will be of chi-bar-square type. The main issue here is to determine the least favorable distribution which is stochastically largest within the class of null distributions.

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Evaluation on Corrosion Behaviour and Adhensivity of Oxide Coated Materials (산화물 피복강재의 부식거동 및 밀착성 평가)

  • Lee Jong-Rark
    • Journal of the Korean Institute of Gas
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    • v.2 no.4
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    • pp.34-41
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    • 1998
  • To oxide film, $A1_2O_3,\;Ta_2O_5$ and $ZrO_2$, coated on stainless steel (SUS410, SUS304) and pure Fe using RF magnetron sputtering method, the corrosion resistance on oxide coatings was studied using electrochemical measurement. Also, the adherence between film and substarte was studied. The adherence index ( $\chi$ ) was determined by the measure of micro hardness test. In this paper, we know that oxide film coated on SUS304 have better corrosion resistance than that coated on SUS410. In oxide film, the difference of corrosion resistance due to crystal structure have not been showed. In evaluating defect area rate of ceramic coated materials, CPCD method can be used effectively. In the micro-hardness test, with $1{\mu}m$ thickness film, it has only one the value of $\chi$. Above $2{\mu}m$ thickness film, however, get another value of $\chi$ as the cracks in film. The oxide film adhere well on the mild materials such as pure steel than high intensity materials like stainless.

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The Diagnostic Assessment of Hand Elevation Test in Carpal Tunnel Syndrome

  • Ma, HyunJin;Kim, Insoo
    • Journal of Korean Neurosurgical Society
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    • v.52 no.5
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    • pp.472-475
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    • 2012
  • Objective : The aim of this study is to establish the value of hand elevation test as a reproducible provocative test for the diagnosis of carpal tunnel syndrome (CTS). Methods : We had a prospective study of 45 hands of 38 patients diagnosed with CTS between April 2005 and February 2009. The diagnosis of CTS was based on the American Academy of Neurology clinical diagnostic criteria. Experimental and control group patients underwent Tinel's test, Phalen's test, carpal compression test and hand elevation test as provocative tests for CTS. Results : We used chi-square analysis to compare Tinel's test and Phalen's test, carpal compression test with hand elevation test. The sensitivity and specificity of the hand elevation test is 86.7% and 88.9% each. Tinel's test had 82.2% sensitivity and 88.9% specificity. Phalen's test had 84.4% sensitivity and 86.7% specificity. Carpal compression test had 84.4% sensitivity 82.2% specificity. Comparisons of sensitivity and specificity between hand elevation test and Tinel's test, Phalen's test, and carpal compression test had no statistically significant differences. To compare the diagnostic accuracies of four tests, the area under the non-parametric receiver operating character curve was applied. Conclusion : The hand elevation test has higher sensitivity and specificity than Tinel's test, Phalen's test, and carpal compression test. Chi-square statistical analysis confirms the hand elevation test is not ineffective campared with Tinel's test, Phalen's test, and carpal compression test.

Convergence Effect of Horticulture Activity Program on Self-esteem and School Life Adaptation of Multicultural Adolescent. (원예활동프로그램이 다문화청소년의 자아존중감과 학교생활적응에 미치는 융합효과)

  • Ha, Yoon-Joo;Kim, Eun-A
    • Journal of Digital Convergence
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    • v.17 no.6
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    • pp.409-416
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    • 2019
  • The purpose of this study was to investigate the effect of horticulture activity program on self-esteem and school life adaptation of multicultural adolescent. A non-equivalent control group pre-post test design with experimental group (n=39) and control group (n=36) was used. The program was conducted from Jan. 2 to Feb. 28, 2017, and the questionnaire was conducted before and after the program. Collected data was analyzed by SPSS(Ver, 24.0), conducting ${\chi}^2-test$, Fisher's exact test, t-test, paired t-test. There were statistically significant increase in self-esteem(t=2.41, p=.021) and school life adaptation(t=3.85, p=.000) by difference between a pretest and a posttest in the experimental group compared to that in the control group. Therefore, the horticulture activity program for multicultural adolescent have a significant effect for better performance of self-esteem and school life adaptation. Also, It was confirmed that the program used for improving adaptability of multicultural adolescent.

Influencing Factors of Intention of Undergoing Pap Testing among Unmarried Nurses (미혼 간호사의 Pap 검진의도 영향요인)

  • Kim, Hae Won
    • Women's Health Nursing
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    • v.20 no.3
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    • pp.225-233
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    • 2014
  • Purpose: This study was to assess the intention of undergoing Pap testing and to identify influencing factors of HPV knowledge and their attitude related to Pap test by sexual activity among unmarried nurses. Methods: A cross sectional survey design was employed, utilizing a self-administered questionnaire amongst 343 unmarried nurses. Descriptive statistics was utilized to analyze data and inferential statistics used an independent-t test and ${\chi}^2$ test for the differences in measurement variables, and odds ratios for factors on intention of Pap testing by sexual activity. Results: Nurses not sexually active were significantly higher in intention of Pap testing (${\chi}^2$=40.15, p<.001) and influencing factors of HPV knowledge (t=3.93, p=.048) than did nurses who were sexually active. Factors influencing intention were regularity of the breast self-examination (Adjusted Odds Ratio [AOR]=4.20, 95% Confidence Interval [CI]=1.93~9.17), HPV knowledge (AOR=2.49, 95% CI=1.36~4.56), and attitudes toward the Pap test(AOR=2.33, 95% CI=1.25~4.34) amongst nurses who never had sexual experience. Conclusion: It is necessary to minimize negative attitudes of Pap testing and to increase HPV knowledge in order to improve intention of Pap testing for women who were not sexually active. More focus would be given to sexually active women to get Pap tested as a preventive measure for cervical cancer.

Cardiovascular Disease According to Job Type and Life Style (근로 형태와 생활습관에 따른 심혈관계 질환 차이)

  • Yoon, Wan-Young
    • Journal of Digital Convergence
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    • v.14 no.2
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    • pp.501-507
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    • 2016
  • We obtained medical test data of 150 male from National Health Insurance Corporation, that included physique, blood chemistry, and lifestyle. ${\chi}^2-test$ and logistic regression, and multiple regression were done to verify how CAD risks and/or lifestyle are different between obese and non-obese person. SPSS(version 18) was used for statistical procedures and p-value of .05 was regarded as good through. ${\chi}^2-test$ showed the frequency of hypertension, htperglycemia, hyperlipidemia were higher in obese person than in non-obese This result told us that lifestyle modification could be a key to prevent cardiovascular disease by controlling and managing body composition, especially abdominal obesity.

Two-sample chi-square test for randomly censored data (임의로 관측중단된 두 표본 자료에 대한 카이제곱 검정방법)

  • 김주한;김정란
    • The Korean Journal of Applied Statistics
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    • v.8 no.2
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    • pp.109-119
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    • 1995
  • A two sample chi-square test is introduced for testing the equality of the distributions of two populations when observations are subject to random censorship. The statistic is appropriate in testing problems where a two-sided alternative is of interest. Under the null hypothesis, the asymptotic distribution of the statistic is a chi-square distribution. We obtain two types of chi-square statistics ; one as a nonnegative definite quadratic form in difference of observed cell probabilities based on the product-limit estimators, the other one as a summation form. Data pertaining to a cancer chemotheray experiment are examined with these statistics.

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Effect of Tai Chi Exercise Program on Muscle Strength, Grip Strength, Flexibility, Pain, Depression and Self-efficacy in Patients with Osteoarthritis (골관절염 환자에게 적용한 타이치운동이 하지근력, 악력, 유연성, 통증, 우울 및 자기효능감에 미치는 효과)

  • Chang, Koung-Oh
    • Journal of muscle and joint health
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    • v.15 no.2
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    • pp.130-139
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    • 2008
  • Purpose: The purpose of this study was to examine the effect of Tai Chi exercise on muscle strength, grip strength, flexibility, pain, depression and self-efficacy in patients with osteoarthritis. Method: With a quasi-experimental design, 46 persons with osteoarthritis were assigned into an experimental group (n=22) or a control group (n=24). Muscle strength, grip strength, flexibility, pain, depression and self-efficacy were measured both before and after the exercise. Data were analyzed with SPSS WIN using descriptive statistics, t-test, and ANCOVA. Results: The mean age of the subjects was 68 years in the experimental group and 64 years in the control group. After controlling for age and pre-test outcome variables, muscle strength scores (F=-14.8, p= .00), grip strength scores (Rt: F=8.40, p= .01), and self-efficacy (F=47.3, p= .00) improved more in the experimental group than the control group. Joint pain scores (F=15.0, p= .00) and depression scores (F=14.7, p= .00) decreased in the experimental group. Conclusion: Tai Chi exercise is likely to be an effective nursing intervention to improve muscle strength, grip strength, and self-efficacy and reduce pain and depression for patients with osteoarthritis.

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Graph-based modeling for protein function prediction (단백질 기능 예측을 위한 그래프 기반 모델링)

  • Hwang Doosung;Jung Jae-Young
    • The KIPS Transactions:PartB
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    • v.12B no.2 s.98
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    • pp.209-214
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    • 2005
  • The use of protein interaction data is highly reliable for predicting functions to proteins without function in proteomics study. The computational studies on protein function prediction are mostly based on the concept of guilt-by-association and utilize large-scale interaction map from revealed protein-protein interaction data. This study compares graph-based approaches such as neighbor-counting and $\chi^2-statistics$ methods using protein-protein interaction data and proposes an approach that is effective in analyzing large-scale protein interaction data. The proposed approach is also based protein interaction map but sequence similarity and heuristic knowledge to make prediction results more reliable. The test result of the proposed approach is given for KDD Cup 2001 competition data along with those of neighbor-counting and $\chi^2-statistics$ methods.