We derive asymptotic properties of estimators and test statistics to determine - in a grouped data setting - common versus group-specific factors. Despite the fact that our test statistic for the number of common factors, under the null, involves a parameter at the boundary (related to unit...

Currently, consumer behavior is influenced by trends that are clearly noticeable at different levels. Some organizations monitor changes in consumption and, on this basis, point to the general tendencies that are typical of today's consumers. The reason why retro marketing has become...

The competitive nature of business today requires the knowledge to be able to manipulate process levels in a predictable fashion and to reduce process variation (quality control). This goal can beachieved through the use of experimentation to identify and confirm the effects of the process...