Let $X_1, \ldots, X_n$ be mutually independent exponential random variables with distinct hazard rates $\lambda _1, \lambda _n$ and let $Y_1, Y_n$ a sample from the distribution rate $\bar = \sum _{i=1}^{n} _i/n$ . Also $X_{1:n} \lt \cdots X_{n:n}$ $Y_{1:n} Y_{n:n}$ their associated order statistics. It is proved that for $1\le i j \le n$ , generalized spacing $X_{j:n} - X_{i:n}$ more dispersed...

Hoffman et al. proposed a convenient collapsibility test in Cox regression [1]. Collapsibility tests have been considered as an effective way to select confounders to be included in multiplicative rate models [2]. However, it is not reasonable to expect that the performance of a confounder-selection procedure (CSP) using the Hoffman’s test is as shown in [2]. First, unlike multiplicative rate m...

Finbarr Department ofI:sio~;tatisti(;s University of 'Wa:5hirlgtcm Seattle. WA

All rights reserved. Short sections of text, not to exceed two paragraphs, may be quoted without explicit permission, provided that full acknowledgement is given. 1 ABSTRACT This paper investigates the transition from high school to first job using data from the National Education Longitudinal Study 1988-2000. A proportional hazards model is estimated to identify the determinants of time-to-fir...

This power function can be used to • compute the power β with which the hypothesis test rejects a specific alternative ω1 > ω0 when the sample size is at some given value of n; • compute the sample size for which a hypothesis test would have prescribed power β to detect a specific “design” alternative ω1 > ω0; or • compute the alternative ω1 > ω0 which is rejected with prescribed power β when p...

W e investigate relationships between operational capabilities and new venture survival. On the basis of operations management and entrepreneurship literature, we develop a contingency framework of operational capabilities especially appropriate at different life phases of a new venture’s evolution. We expect that in the first years of a new venture’s life, entrepreneurs should emphasize high i...

In a polygamous society, all monogamous women are virtually at risk of polygamy. However, both the anthropological and economic literature are silent on the potential impact of the risk of polygamy on economic decisions of monogamous wives. We explore this issue for Senegal using individual panel data. We first estimate a Cox model for the probability of transition to polygamy. Second, we estim...