Piero Quatto

Spline functions are a very flexible and powerful tool, which has been adopted in several applied fields, such as the evaluation of Public Services. In this paper, we use splines to model membership and non-membership functions in the context of Intuitionistic Fuzzy Sets...

In this paper we consider the problem of measuring latent variables with ordinal scales and we put forward an original approach to this issue, which combines the use of Intuitionistic Fuzzy Sets with the calculation of bipolar means and bipolar distributions. Intuitionistic Fuzzy theory allows a researcher to model the degree of membership and non-membership to a certain fuzzy set, as well as the residual uncertainty...

In wildlife population studies one of the main goals is estimating the population density. Line transect sampling is a well established methodology for this purpose. The usual approach for estimating the density of the population of interest is to assume a particular model for the detection function. The estimates are extremely sensitive to the shape of the detection function, particularly to the socalled shoulder condition, which ensures that an animal is nearly certain to be detected if it is at a small distance from the observer. For instance, the half-normal model satisfies this condition whereas the negative exponential does not. So, testing whether the shoulder condition is consistent with the data is a primary concern. Since the problem of testing such a hypothesis is invariant under the group of scale transformations, in this paper we propose the uniformly most powerful test in the class of the scale invariant tests for the half-normal model against the negative exponential model. The asymptotic distribution of the test statistic is derived. The critical values and the power are tabulated via Monte Carlo simulations for small samples.

The aim of this paper is twofold: firstly to point out the inadequacy of the “Kappa” statistic in the context of University Student Satisfaction; secondly to propose a procedure for assessing and testing agreement among multiple raters which is based on a statistic not affected by “Kappa” paradoxes.