Walter Maffenini
Titoli dell'autore
The potential of the I(p) inequality curve in the analysis of empirical distributions
digital

Anno:
2015
The possibility of analysing the inequality of a frequency distribution through a point measure is undoubtedly an advantage for any socioeconomic research. The Lorenz curve is the cornerstone on which other global inequality measures have been subsequently introduced...
The regression estimator in presence of ‘‘not at home’’
Gratis
digital
Anno:
2008
Being temporarily not at home can often cause the impossibility to give out a questionnaire to each
selected unit of a sample; moreover, a high percentage of nonrespondents can strongly affect the
quality of estimates. In order to solve this problem the ‘‘not at home’’ are usually called back until
they become available; however, this methodology highly increases the costs of a survey.
The main idea of this paper traces back to an estimation method early proposed by Politz and Simmons;
in particular, a new estimator, based on the regression method, is proposed, so that the auxiliary
information about the number of evenings spent at home by the units of the target population
can be used. The proposed estimator is shown to be unbiased and more efficient than the one based
only on the responses of the units being at home when first contacted. Moreover, unlike from the
Politz-Simmons estimator, the variance of the proposed estimator can be easily determined and
computed. Finally, in order to discuss the asymptotic properties of the regression estimator, the results
of some simulations are reported; both the proposed estimator and the Politz-Simmons one
turn out to be asymptotically unbiased; however, the regression estimator still proves to be more efficient.
Using the properties of the arithmetic mean for least squares interpolation
Gratis
digital
Anno:
2007
In the present paper some properties of the arithmetic mean have been employed to determine the
parameters of the least squares line, plane and hyper plane, without using partial derivatives and
solving the equations of the normal system. It is in fact known that when the criterion of least
squares is used to identify an interpolating function, the solution to the problem is obtained via the
search for the minimum of a function; therefore the use of partial derivatives becomes inevitable. Instead,
the method here suggested allows the interpolating model - which is common to many economic
and social subjects - to be presented to university students including those without any knowledge
of partial derivatives.
Minimum sample sizes for confidence intervals for Gini’s mean difference: a new approach for their determination
Gratis
digital
Anno:
2007
The sample mean difference  is an unbiased estimator of Gini’s mean difference A. It is well
known that  is asymptotically normally distributed (Hoeffding, 1948). In order to obtain confidence
intervals for A, Â must be standardized and hence its variance Var(Â) must be estimated. In
this paper we study the effective coverage of the confidence intervals for A, when using a specific
unbiased estimator ^ Var(Â) for the variance of Â, in a non-parametric framework. The empirical
determination of the minimum sample size required to reach a good approximation of the nominal
coverage is analyzed through a new approach. The reported results show that this threshold is critically
related to the asymmetry and the tail heaviness in the underlying distribution.
Bipolar mean and mean deviation about the bipolar mean for discrete quantitative variables
digital

Anno:
2006
In this paper, the bipolar mean, that can be seen as a frequencies distribution, has been extended to the discrete variables.
Bipolar mean for ordinal variables
digital

Anno:
2005
This paper proposes, for ordinal variables, a new type of mean called bipolar mean, that is a frequency distribution with the total size n concentrated on one category or on two consecutive categories.
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