Browsing by Author "Wang, J.-L."

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Open Access
A comparison of hazard rate estimators for left truncated and right censored data
(1992) Uzunoğulları, Ü.; Wang, J.-L.
SUMMARY: Left truncation and right censoring arise frequently in practice for life data. This paper is concerned with the estimation of the hazard rate function for such data. Two types of nonparametric estimators based on kernel smoothing methods are considered. The first one is obtained by convolving a kernel with a cumulative hazard estimator. The second one is in the form of a ratio of two statistics. Local properties including consistency, asymptotic normality and mean squared error expressions are presented for both estimators. These properties facilitate locally adaptive bandwidth choice. The two types of estimators are then compared based on their theoretical and empirical performances. The effect of overlooking the truncation factor is demonstrated through the Channing House data.
Open Access
On the Hajek projection for truncated and censored data
(Scientific Publishers, 1993) Gürler, Ü.; Wang, J.-L.
Large sample properties of the product-limit estimators for truncated or censored data are usually achieved via the empirical cumulative hazard function estimators. Hajek projection of the empirical cumulative hazard function estimator is derived for truncated data and expressed for censored data. It turns out that both projections are asymptotically ni-equivalent but not equal to the respective influence curves. Weak convergences of the empirical cumulative hazard processes are deduced accordingly.