• 제목/요약/키워드: Statistical significance test

검색결과 1,526건 처리시간 0.026초

상엽 물추출물이 다이옥신 유도 독성에 대한 흰쥐의 혈액 생화학지표에 미치는 영향 (The Effect of Mulberry Leaf Extract on Blood biochemical parameters in White Rats Exposed to 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD))

  • 이윤복;배수정;이다경;박재승;박지원;김병원;황석연
    • 디지털융복합연구
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    • 제11권1호
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    • pp.299-308
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    • 2013
  • TCDD 독성이 유발된 흰쥐 혈액의 생화학적 지표에 미치는 상엽 물추출물 (MLE)의 효과를 조사하였고 통계자료는 일원분산분석과 Scheffe의 사후검증을 하였다. TCDD 투여 시 감소했던 백혈구와 혈소판의 수가 MLE투여로 급격하게 회복(p<0.01)되어 면역기능 개선효과가 있었다. TT에 의해 감소했던 혈중 칼슘 및 마그네슘의 농도는 MLE 투여 시 유의하게 증가(p<0.01)하였으나 인의 농도는 TT군에 비하여 MLE군이 유의하게 감소(p<0.01)하였다. 신장 기능과 관련된 creatinine 및 blood urea nitrogen은 TT군과 MLE군 사이에 유의성은 없었으며, 요산은 TT군과 MLE군 모두에서 감소하였다. 한편 TT에 의해 증가했던 glucose 농도, amylase 및 lipase의 효소 활성도는 MLE 투여시 유의하게 감소(p<0.01)하여 혈당상승 억제효과가 있었다. Total protein, ${\gamma}$-GTP 활성은 TT와 MLE의 영향을 거의 받지 않았으나 TT에 의해 증가했던 AST, ALT 및 ALP의 활성도는 MLE 투여 시 모두 유의하게 감소(p<0.01)하여 간기능 개선의 효과가 있었다. 한편 Total cholesterol, triglyceride와 LDL-cholesterol의 경우 TT에 의해 유발된 고지혈 증상이 MLE 투여 시 유의하게 감소(p<0.01)하여 항고지혈 효과가 있었으며 HDL-cholesterol은 TT군과 MLE군 모두에서 증가하였다. 이와 같이 MLE는 TCDD독성이 유발된 흰쥐에서 독성을 완화시켜 주는 작용이 있음을 알 수 있었다.

CONFLICT AMONG THE SHRINKAGE ESTIMATORS INDUCED BY W, LR AND LM TESTS UNDER A STUDENT'S t REGRESSION MODEL

  • Kibria, B.M.-Golam
    • Journal of the Korean Statistical Society
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    • 제33권4호
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    • pp.411-433
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    • 2004
  • The shrinkage preliminary test ridge regression estimators (SPTRRE) based on Wald (W), Likelihood Ratio (LR) and Lagrangian Multiplier (LM) tests for estimating the regression parameters of the multiple linear regression model with multivariate Student's t error distribution are considered in this paper. The quadratic biases and risks of the proposed estimators are compared under both null and alternative hypotheses. It is observed that there is conflict among the three estimators with respect to their risks because of certain inequalities that exist among the test statistics. In the neighborhood of the restriction, the SPTRRE based on LM test has the smallest risk followed by the estimators based on LR and W tests. However, the SPTRRE based on W test performs the best followed by the LR and LM based estimators when the parameters move away from the subspace of the restrictions. Some tables for the maximum and minimum guaranteed efficiency of the proposed estimators have been given, which allow us to determine the optimum level of significance corresponding to the optimum estimator among proposed estimators. It is evident that in the choice of the smallest significance level to yield the best estimator the SPTRRE based on Wald test dominates the other two estimators.

Development of wall-thinning evaluation procedure for nuclear power plant piping - Part 2: Local wall-thinning estimation method

  • Yun, Hun;Moon, Seung-Jae;Oh, Young-Jin
    • Nuclear Engineering and Technology
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    • 제52권9호
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    • pp.2119-2129
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    • 2020
  • Flow-accelerated corrosion (FAC), liquid droplet impingement erosion (LDIE), cavitation and flashing can cause continuous wall-thinning in nuclear secondary pipes. In order to prevent pipe rupture events resulting from the wall-thinning, most NPPs (nuclear power plants) implement their management programs, which include periodic thickness inspection using UT (ultrasonic test). Meanwhile, it is well known in field experiences that the thickness measurement errors (or deviations) are often comparable with the amount of thickness reduction. Because of these errors, it is difficult to estimate wall-thinning exactly whether the significant thinning has occurred in the inspected components or not. In the previous study, the authors presented an approximate estimation procedure as the first step for thickness measurement deviations at each inspected component and the statistical & quantitative characteristics of the measurement deviations using plant experience data. In this study, statistical significance was quantified for the current methods used for wall-thinning determination. Also, the authors proposed new estimation procedures for determining local wall-thinning to overcome the weakness of the current methods, in which the proposed procedure is based on analysis of variance (ANOVA) method using subgrouping of measured thinning values at all measurement grids. The new procedures were also quantified for their statistical significance. As the results, it is confirmed that the new methods have better estimation confidence than the methods having used until now.

경도근시(가성근시 포함) 환자에 있어 눈 경혈 마사지기와 침치료간의 증상개선 효과 비교를 위한 임상시험(단일기관, 무작위 배정) (The Clinical Tests for Treatment Improvement Comparison in Myopia between Eye Acupuncture Massage Machine (NURIEYE-1) and Acupuncture)

  • 김미보;김규곤;홍상훈;고우신;윤화정
    • 한방안이비인후피부과학회지
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    • 제22권3호
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    • pp.80-94
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    • 2009
  • Objective : The purpose of this clinical research is the investigation of the effects between acupuncture group(control group) and NURIEYE-1 group (experimental group) in myopia Methods : Comparison clinical study was conducted with the randomly arranged 32 patients for acupuncture group(control group) and NURIEYE-1 group(experimental group). For effectiveness evaluation, eye sight test, MQOL and DITI were tested three times with visits for every 4 weeks. With SAS, Statistical analysis was performed by using paired t-test and two sample t-test. Statistical significance was achieved with less than 5% probability (p<0.05). Result : 1. There was no significant effect from the eye sight comparison between the two group. We had improved results in average with MQOL, however, there was no statistical significance. Though there was also no significant result with DITI average comparison between two group, we witnessed significant effect in some part of MQOL. 2. Nevertheless Periodical comparison test showed weak significance with eye sight and DITI, significant effect was found in some part of MQOL. 3. With periodical comparison tests, there were significant effects in eye sight, MQOL and DITI with the experimental groups and control groups, respectively. Conclusion : There was no significant eye sight improvement. However, with acupuncture point stimulation, we think there are some positive effects for the relaxation of excessive stress in eyes.

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반복측정 자료에서 개제기올기를 이용한 대존군과 처리군들의 선형추세 검정법 (Linear Trend Comparison of Repeated Measures Data among Treatments with a Control)

  • 권재흔;김동재
    • Communications for Statistical Applications and Methods
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    • 제16권6호
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    • pp.945-957
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    • 2009
  • 의약학 분야에서는 여러 집단에서 하나의 반복요인을 가지는 반복측정 자료가 많이 사용된다. 이 논문에서는 대조군과 처리군들의 시간에 따른 반응값의 선형추세를 비교하기 위하여 각 개체의 기울기를 추정하고 추정된 기울기들에 의해 생생된 표본으로 F-test, Jonckheere-Terpstra test, updated control group procedure를 이용하여 대조문과 처리군들의 차이를 검정하는 방법을 제안하였다. 모의실험 (Monte Carlo Simulation)을 통해 실험유의수준(experimental significance level)과 검정력(power)을 비교하였다.

수동운동이 측두하악관절 가동범위 증가에 미치는 효과 (The Effect of Passive Movement on Range of Motion in Temporomandibular Joint)

  • 이효정;송주영
    • The Journal of Korean Physical Therapy
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    • 제19권4호
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    • pp.43-51
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    • 2007
  • Purpose: The purpose of this study was to determine the effects on improvement of the range of motion in the TM joint. Methods: 26 subjects who have TM joint limitation were divided to passive movement group(n=13, $21.3{\pm}2.95$ years) and active movement group(n=13, $20.62{\pm}1.39$ years). All of the subjects were treated 5 to 10 minutes per one time, five times once a week for 4 weeks by the physical therapist. The open bite and cross bite were investigated at before, during(2 wks) and treatment(4 wks). Results: In order to assure the statistical significance of the result, a Repeated measures ANOVA were applied at the 0.05 level of the significance. There was a significant difference in terms of the rates of open bite mean change in within-open bite effects among pre-test, post-test 2weeks and post-test 4weeks in each group(P=0.029). There was no significant difference in the rates of mean change in between-open bite effects(P=0.441) but interactions between two types of effects(P=0.025) were statistical significance among pre-test, post-test 2 weeks and post-test 4 weeks in each group. There was no significant difference in the rates of mean change in within-close bite effects(P=0.112), between-cross bite(P=0.179) and interactions between the two types of effects(P=0.098) among pre-test, post-test 2 weeks and post-test 4 weeks in each group. Conclusion: The results of this study showed that passive movement and active movement were effect on increase of TM joint ROM about open bite and cross bite.

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Use of the estimated critical values adapting a regression equation for the approximate entropy test

  • 차경준;류제선
    • Journal of the Korean Data and Information Science Society
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    • 제13권2호
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    • pp.77-85
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    • 2002
  • The statistical testing methods have been widely recognized to determine the plain and cipher texts. In fact, the randomness for a sequence from an encryption algorithm is necessary to guarantee security and reliance of cipher algorithm. Thus, the statistical randomness tests are used to discover cipher text. In this paper, we would provide the critical value for an approximate entropy test by estimating the nonlinear regression equation when the number of sequence and the level of significance are given. Thus, we can discern plan and cipher text for real problem with given number of sequence and the level of significance. Also, we confirm the fitness of the estimated critical values from the rate of success for plain or cipher text.

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Controling the Healthy Worker Effect in Occupational Epidemiology

  • 김진흠;남정모
    • 한국통계학회:학술대회논문집
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    • 한국통계학회 2002년도 추계 학술발표회 논문집
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    • pp.197-201
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    • 2002
  • The healthy worker effect is an important issue in occupational epidemiology. We proposed a new statistical method to test the relationship between exposure and time to death in the presence of the healthy worker effect. In this study, we considered the healthy worker hire effect to operate as a confounder and the healthy worker survival effect to operate as a confounder and an intermediate variable. The basic idea of the proposed method reflects the length bias-sampling caused by changing one's employment status. Simulation studies were also carried out to compare the proposed method with the Cox proportional hazards models. According to our simulation studies, both the proposed test and the test based on the Cox model having the change of the employment status as a time-dependent covariate seem to be satisfactory at an upper 5% significance level. The Cox models, however, are inadequate with the change, if any, of the employment status as time-independent covariate. The proposed test is superior in power to the test based on the Cox model including the time-dependent employment status.

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The Nonparametric Test for Detecting Main Effects for Three-Way ANOVA Models

  • Park, Young-Hun
    • Journal of the Korean Statistical Society
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    • 제25권3호
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    • pp.419-432
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    • 1996
  • When interactions are not present in a three-way layout, the lim-iting null distribution of the F statistic for testing main effects when applied to the rank-score transformed data is the same as the limiting null distribution of the usual F statistic when applied to the normal data. The simulation results exhibit that the rank transform test is robust with respect to significance level and powerful for testing main effects in a three-way factorial experiment.

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Prognostic Factors of Idiopathic Facial Palsy: A Retrospective Study

  • Park, Gi Nam;Jeong, Jeong Kyo;Kim, Eun Seok;Kim, Jung Ho;Kim, Young Il
    • Journal of Acupuncture Research
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    • 제34권3호
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    • pp.23-38
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    • 2017
  • Objectives : The purpose of this study was to evaluate the clinical prognostic factors affecting facial palsy in 98 idiopathic facial palsy patients who were hospitalized and treated in 2015, using retrospective statistical analysis. Methods : We investigated patients with idiopathic facial nerve palsy, admitted to a Korean medical hospital in 2015, and examined patients' variables and therapeutic variables. For analysis of clinical data, an independent sample t-test, analysis of variance (ANOVA), and simple regression analysis were performed using IBM SPSS version 24.0. Results : 1. The initial degree of facial palsy showed statistical significance with age. The older the age, the more severe the initial palsy. 2. Following treatment degree of facial palsy was statistically significant with age, hypertension, and fasting blood sugar (FBS). The higher the value, the slower the recovery from facial palsy. There was a statistical significance with the number of treatments in a Korean medical hospital. The more frequent the treatment, the faster the facial palsy recovery. 3. Degree of facial palsy after 12 months was statistically significant with age, hypertension, diabetes, FBS, and the initial severity of facial palsy. The higher the value, the slower the facial palsy recovery. 4. Sex, left or right sided palsy, alcohol consumption, smoking, history of facial palsy, season of onset, total number of treatments and bio chemistry (BC), complete blood cell count (CBC), urinalysis (UA) factors had no statistical significance with prognosis of facial palsy. Conclusion : Age, season of onset, hypertension, diabetes, FBS, initial severity of facial palsy, and the number of treatments at a Korean medical hospital showed statistical significance. The number of treatments at the Korean medical hospital positively correlated with facial palsy prognosis, and the others variables showed a negative correlation with facial palsy prognosis.