• Journal of the Korean Home Economics Association
• /
• v.33 no.2
• /
• pp.19-27
• /
• 1995

This paper discusses the bias that results from using nonrandomly selectd samples of consumer research. A two stage system (maximum likelihood probit analysis and ordinary least square analysis) is a solution to sample selection bias. Empirical results show that correcting for sample selection bias improves the validity of consumer research results.

• Journal of the Korean Data and Information Science Society
• /
• v.12 no.2
• /
• pp.71-82
• /
• 2001

There are several ways to test the equality of two survival distributions under a variety of situations. Tests for equality of two distributions with life-table model for univariate independent response times are reviewed and introduced. It is developed that the methodology to test it for correlated response times where treatments are applied to different independent sets of cohorts. Data, which can be separated into two independent sets, from an angioplasty study where more than one procedure is performed on some patients are used to illustrate this methodology.

• Journal of the Korean Data and Information Science Society
• /
• v.15 no.3
• /
• pp.677-687
• /
• 2004

We consider the comparison of two one-parameter exponential distributions with the complete data as well as the type II censored data. We adapt Bayesian test procedure for nested hypothesis based on the Bayesian reference criterion. Specifically we derive the expression for the Bayesian reference criterion to solve our problem. Also we provide numerical examples using simulated data sets to illustrate our results.

• Journal of the Korean Data and Information Science Society
• /
• v.15 no.3
• /
• pp.625-632
• /
• 2004

We consider the empirical Bayes confidence intervals that attain a specified level of EB coverage for the scale parameter in the Burr distribution under type II censoring data. Also, we compare the coverage probabilities and the expected confidence interval lengths for these confidence intervals through simulation study.

• ETRI Journal
• /
• v.18 no.3
• /
• pp.207-213
• /
• 1996

This paper proposes a new nonparametric test for testing the null hypothesis that the MRL is constant against the alternative hypothesis that the MRL is decreasing (increasing) for ramdomly censored data. The proposed test statistic is a L-statistic, and we use L-statistic theory to establish its asymptotic normality of the test statistic. We discuss the efficiency loss due to censoring and also calculate the asymptotic relative efficiencies of our test statistic with respect to the Chen, Hollander and Langberg's test for several alternatives.

• Journal of the Korean Data and Information Science Society
• /
• v.16 no.2
• /
• pp.457-465
• /
• 2005

We consider the estimation of parameter in the exponential model in the case that the number of replacements of failed items is limited. And the desirable number of replacements to give the similar effect as unlimited case in terms of the mean square errors is proposed.

• Journal of the Korean Data and Information Science Society
• /
• v.5 no.1
• /
• pp.59-66
• /
• 1994

Heller and Simonoff(1990) compared several methods of estimating the regression coefficient in a modified proportional hazards model, when the response variable is subject to censoring. We give another method of estimating the parameters in the model which also allows the dependent variable to be censored and the error distribution to be unspecified. The proposed method differs from that of Miller(1976) and that of Buckely and James(1979). We also obtain the variance estimator of the coefficient estimator and compare that with the Buckely-James Variance estimator studied by Hillis(1993).

• Journal of the Korean Data and Information Science Society
• /
• v.10 no.1
• /
• pp.47-56
• /
• 1999

In this paper, for whole line ($0,\;{\infty}$), the estimation procedure of mean residual life function using product-limit estimator is studied with asymptotic properties. And also, the small sample properties of proposed estimator of MRLF are investigated through Monte Carlo study and compared with Kaplan-Meier type estimator.

• Journal of the Korean Data and Information Science Society
• /
• v.10 no.1
• /
• pp.57-65
• /
• 1999

In a resent paper, Na, Lee and Kim(1998) develop a test statistic for testing whether or not the mean residual life changes its trend based on complete data and show that the new test performs better than previously known tests. In this paper, we extend their test to the randomly censored data. The asymptotic normality of the test statistic is established. Monte Carlo simulations are conducted to compare our test with a previously known test by the power of tests.

• Journal of the Korean Data and Information Science Society
• /
• v.15 no.1
• /
• pp.31-39
• /
• 2004

In this paper, we consider two components system which the lifetimes follow bivariate pareto model with bivariate random censored data. We assume that the censoring times are independent of the lifetimes of the two components. We develop large sample test for testing independence between two components. Also we present a simulation study which is the test based on asymptotic normal distribution in testing independence.