Regression specifications frequently employ regressors that are defined as the product of two other regressors to form an interaction. Unfortunately, these models have a number of potential difficulties when it comes to interpretation. In this paper, we discuss two common aspects of these...

This paper extends commonly used tests for equality of hazard rates in a two-sample or k-sample setup to a situation where the covariate under study is continuous. In other words, we test the hypothesis that the conditional hazard rate is the same for all covariate values, against the omnibus...

AMS classifications: 90D12, 90C05.

AMS classifications: 90A15, 90D12.

A polemics with the opinion that power laws generically appear in systems with finite resources is carried on. Examples of simple models of redistribution of resources which lead to short-tail distributions are given. It is shown that the true cause of inverse-power distributions is some kind of...