• Title/Summary/Keyword: two sample testing

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k-Sample Rank Procedures for Ordered Location-Scale Alternatives

  • Park, Hee-Moon
    • Journal of Korean Society for Quality Management
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    • v.22 no.2
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    • pp.166-176
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    • 1994
  • Some rank score tests are proposed for testing the equality of all sampling distribution functions against ordered location-scale alternatives in k-sample problem. Under the null hypothesis and a contiguous sequence of ordered location-scale alternatives, the asymptotic properties of the proposed test statistics are investigated. Also, the asymptotic local powers are compared with each others. The results show that the proposed tests based on the Hettmansperger-Norton type statistic are more powerful than others for the general ordered location-scale alternatives. However, the Shiraishi's tests based on the sum of two Bartholomew's rank analogue statistics are robust.

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Goodness-of-Fit-Test from Censored Samples

  • Cho, Young-Suk
    • Journal of the Korean Data and Information Science Society
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    • v.17 no.1
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    • pp.41-52
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    • 2006
  • Because most common assumption is normality in statistical analysis, testing normality is very important. The Q-Q plot is a powerful tool to test normality with full samples in statistical package. But the plot can't test normality in type-II censored samples. This paper proposed the modified the Q-Q plot and the modified normalized sample Lorenz curve(NSLC) for normality test in the type-II censored samples. Using the two Hodgkin's disease data sets and the type-II censored samples, we picture the modified Q-Q plot and the modified normalized sample Lorenz curve.

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The Program for Teaching on Type I error and Type II error

  • Choi, Hyun-Seok
    • 한국데이터정보과학회:학술대회논문집
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    • 2004.10a
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    • pp.17-23
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    • 2004
  • At the conclusion from the hypothesis testing, there is a possibility of making Type I error and Type II error. The purpose of this article is to use this program in statistics teaching through developing the program for studying on the concept about these two errors, two kinds of the probability of errors by the variation of rejection region, two kinds of the probability of errors by the variation of sample size, the relations of the probability $\alpha$ and $\beta$ by these two errors, and power function, power curve.

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Recent Ultrasonic Guided Wave Inspection Development Efforts

  • Rose, Joseph L.;Tittmann, Bernhard R.
    • Journal of the Korean Society for Nondestructive Testing
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    • v.21 no.4
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    • pp.371-382
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    • 2001
  • The recognition of such natural wave guides as plates, rods, hollow cylinders, multi-layer structures or simply an interface between two materials combined with an increased understanding of the physics and wave mechanics of guided wave propagation has led to a significant increase in the number of guided wave inspection applications being developed each year. Of primary attention Is the ability to inspect partially hidden structures, hard to access areas, and teated or insulated structures. An introduction to some physical consideration of guided waves followed by some sample problem descriptions in pipe, ice detection, fouling detection in the foods industry, aircraft, tar coated structures and acoustic microscopy is presented in this paper. A sample problem in Boundary Element Modeling is also presented to illustrate the move in guided wave analysis beyond detection and location analysis to quantification.

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Testing Hypothesis for the Logistic Model with Estimated Parameters : Modified Tables of Cirticla Values for K-S Type Statistic

  • Hwang, Chung-Sun
    • Journal of the Korean Statistical Society
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    • v.13 no.1
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    • pp.48-56
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    • 1984
  • This paper considers one-sample and two-sample test for the logistic function by means of Kolmororov-Smirnov type statistics. The standard tables used for the Kolmogorov-Smirnov test are valid only when the function is completely specified; but they are not valid if the parameters of function are estimated from the sample. This note presents modified tables for the Kolmogorov-Sminov type staistic. These tables can be used to test the hypothesis that a sample comes from a logistic function when shape parameter $(\alpha)$ and location parameter $(\beta)$ must be estimated from the sample by the method of maximum likelihood. Monte Carlo method is employed to calculate the criticla values of the test. The tables of the critical values are provided.

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Initial sample size problem in the sequential test for the mean of a normal distribution

  • Park, S. C.
    • Journal of the Korean Statistical Society
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    • v.3 no.1
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    • pp.3-12
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    • 1974
  • The two-stage sequential test, suggested by Baker [2] for testing hypotheses $H_0:\mu=\mu_0$ and $H_1:\mu=\mu_1$ of $N(\mu,\sigma^2)$ with the unknown $\sigma^2$ would not be amenable for applications unles some cluses on the choice of the first-stage sample size are available. The study in this paper is intended to shed some light on the size of the first-stage sample. An approximate method is used to estimate an optimal initial sample size that minimizes the average sample number. In brief, the optimal size is a strictly monotone decreasing function of the quantity $(\mu_1-\mu_0)/\sigma$. Empirical and simulation results are used to ascertain the negligible effect of possible errors due to approximations and assumptions used.

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Estimation of Activation Energy of Electroluminescent film by Accelerated Life Test (가속시험을 통한 Electroluminescent film의 활성화 에너지 추정)

  • Kim, Su-Kyoung;Hyung, Jae-Phil;Oh, Gil-Gu;Lim, Hong-Woo;Kim, Myung-Soo;Oh, Geun-Tae
    • Journal of Applied Reliability
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    • v.15 no.1
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    • pp.52-59
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    • 2015
  • In this Study, we tested electroluminescent film to accelerate life by temperature, humidity, voltage, and frequency. We analyzed brightness data to estimate activation energy and verify it's suitability. All of the tests performed in operating condition. Because electroluminescent film is mostly degraded by fluorescent in operating condition. Two different sample groups were tested and compared to find common parameter.

A Comparison of Testing Methods for Equality of Survival Distributions with Interval Censored Data

  • Kim, Soo-Hwan;Lee, Shin-Jae;Lee, Jae-Won
    • The Korean Journal of Applied Statistics
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    • v.25 no.3
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    • pp.423-434
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    • 2012
  • A two-sample test for equality of survival distribution is one of the important issues in survival analysis, especially for clinical and epidemiological research. With interval censored data, some testing methods have been developed. This study introduces some testing methods and compares them under various situations through simulation study. Based on simulation result, it provides some useful information on choosing the most appropriate testing method in a given situation.

A Study on the Two Equal Tail Critical Region for the Testing Statistical Hypothesis (통계적 가설검정에 있어서의 등측기각역에 관한 고찰)

  • 김광섭
    • Journal of Korean Society of Industrial and Systems Engineering
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    • v.5 no.7
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    • pp.25-27
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    • 1982
  • In most introductory statistics courses and text, the two equal tail test is presented without justification. In the present paper, the two equal tail critical region will be discussed in the light of unbiasedness with some test examples for the mean and the variance based on the random sample $X_1$, $X_2$,....$X_n$ from N($\mu$, $\delta^2$) using only elementary mathematics.

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PVC and POM gripping mechanisms for tension testing of FRP bars

  • Basaran, Bogachan;Yaka, Harun;Kalkan, Ilker
    • Structural Engineering and Mechanics
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    • v.77 no.1
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    • pp.75-87
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    • 2021
  • The present study pertains to the introduction of two new types of grip adaptor for universal testing machines, namely Polyvinyl Chloride (PVC) and Polyoxymethylene (POM) grip adaptors, and their application to tension testing of FRP bars with different fiber and surface finish types. The tabs are connected to the FRP bar sample with the help of mechanical anchors, i.e. bolts. These new adaptors offer vital superiorities over the existing end tab designs (anchors with filling material or mechanical anchorage), including the reduction in the time and labor for production, reusability and the mild nature, i.e. low hardness of the tab material, which retards and even prevents peeling and crushing in the gripping regions of an FRP sample. The methods were successfully applied to FRP bars with different types of fiber (CFRP, GFRP and BFRP) and different types of surface texture (ribbed, wrapped, sand-coated and wound). The test results indicated that the both types of end caps prevented slip of the bar, crushing and peeling in the gripping zone. The mechanical properties from the material tests with the new caps were in perfect agreement with the ones from the material tests with steel tubular caps.