• IE interfaces
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• v.16 no.spc
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• pp.65-69
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• 2003

Process capability has long been viewed as a critical performance measure to indicate how well a process meet the specifications and customer requirements. Several indices, including $C_p$ and $C_{pk}$, have been proposed and widely implemented to quantify the process capability. However, these indices have been obtained without regard to inspection or screening procedures through which finished products will be truncated at the specifications. Consequently, only a fraction of outgoing products within the specifications will be passed into the customers. From the customer's point of view, it will thus be meaningful to assess the process capability with truncated samples. This article investigates how to estimate the process capability when only incomplete truncated data are available. On the basis of parameter estimation for truncated samples, the proposed methodology may be helpful to evaluate the process capability by examining a sample of items from the lots submitted.

• Communications for Statistical Applications and Methods
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• v.9 no.1
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• pp.249-259
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• 2002

In order to estimate the mean and variance for a Normal distribution which is truncated at both right and left sides, maximum likelihood estimators based on the entire sample from the original distribution are compared with the sample mean and variance of the censored sample which is the data remaining after truncation using simulation. We found that, surprisingly, the mean squared error of the mean based on the censored data Is smaller than that of the full sample estimators.

• Journal of the Korean Statistical Society
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• v.7 no.2
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• pp.89-94
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• 1978

A procedure for estimating the zero class for a truncated Poisson sample is developed. Asymptotic normality of the estimator is established and a confidence interval for the missing zero class is obtained. This procedure is compared with the method obtained by Dahiya and Gross. Applications are given to illustrate the results obtained.

• Journal of the Korean Statistical Society
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• v.29 no.2
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• pp.169-185
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• 2000

Given a random sample of size N (unknown) with density f(x│$\theta$), suppose that only n observations which lie outside a region r are recorded. On the basis of n observation, the Bayes estimators of $\theta$ and N are considered and their asymptotic expansions are developed to find the third order asymptotic properties with those of the maximum likelihood estimators and the Bayes modal estimators. The asymptotic m.s.e.'s of these estimators are expressed. An example is given to illustrate the results obtained.

• International Journal of Reliability and Applications
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• v.13 no.1
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• pp.19-35
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• 2012

This paper presents an optimum design of step-stress partially accelerated life test (PALT) plan which allows the test condition to be changed from use to accelerated condition on the occurrence of fixed number of failures. Various life distribution models such as exponential, Weibull, log-logistic, Burr type-Xii, etc have been used in the literature to analyze the PALT data. The need of different life distribution models is necessitated as in the presence of a limited source of data as typically occurs with modern devices having high reliability, the use of correct life distribution model helps in preventing the choice of unnecessary and expensive planned replacements. Truncated distributions arise when sample selection is not possible in some sub-region of sample space. In this paper it is assumed that the lifetimes of the items follow Truncated Logistic distribution truncated at point zero since time to failure of an item cannot be negative. Optimum step-stress PALT plan that finds the optimal proportion of units failed at normal use condition is determined by using the D-optimality criterion. The method developed has been explained using a numerical example. Sensitivity analysis and comparative study have also been carried out.

• Journal of the Korean Data and Information Science Society
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• v.6 no.2
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• pp.65-76
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• 1995

The importance of left truncated and right censoring cases has considered for better information in medical follow-up and engineering life testing studies. We propose some estimation procedure for the mean residual life function with consistency and asymptotic normality on the left truncated and right censoring model. And then, the comparision with Kaplan-Meier estimator ignoring the left truncated effect and the small sample properities are investigated by asymptotic biases and M.S.E.'s thresh Monte Carlo study.

• Communications for Statistical Applications and Methods
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• v.1 no.1
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• pp.52-56
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• 1994

When we have an i.i.d. sample of size n from a continuous distribution, the distribution truncated on the left at the rth order statistic plays an important role in the theoretical analysis of the Type 2 censored data. The charaterization of distributions by the average of the conditional expectation and the average of the conditional information concerning the truncated distribution is studied here.

• Journal of the Korean Data and Information Science Society
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• v.17 no.3
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• pp.1021-1028
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• 2006

We shall propose ML, ordinary jackknife and biased reducing estimators of the parameter in the right truncated exponential distribution with an unidentified uniform outlier when the truncated point is unknown and their biases and MSE's are compared numerically each other in the small sample sizes.

• Journal of the Korean Statistical Society
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• v.7 no.2
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• pp.83-83
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• 1978

• Journal of the Korean Data and Information Science Society
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• v.13 no.1
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• pp.147-156
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• 2002

In this paper, we study the properties of the modified winsorized mean to estimate the mean of a two-truncation parameter population. Under some mild conditions, the estimator is found to be strongly consistent and asymptotically unbiased even though the sample is doubly type II censored.