Abstract

We develop a clustering framework for observations from a population with a smooth probability distribution function and derive its asymptotic properties. A clustering criterion based on a linear combination of order statistics is proposed. The asymptotic behavior of the point at which the observations are split into two clusters is examined. The results obtained can then be utilized to construct an interval estimate of the point which splits the data and develop tests for bimodality and presence of clusters.

Highlights

  • We develop a general framework for univariate clustering based on the ideas in Hartigan (1978) for the case of observations from a population with smooth and invertible distribution function

  • Contrary to Hartigan’s approach, which was based on a quadratic function of the observed data, our clustering criterion function possesses the advantage of being a linear combination of order statistics—it is a combination of trimmed sums and sample quantiles

  • We deviate from the Hartigan’s framework and concentrate our attention on a function of the derivative of his split function. This approach permits us to obviate the existence of a finite fourth moment assumption imposed by Hartigan in the asymptotic investigation of his criterion function—a second moment assumption at the cost of an additional smoothness condition on our criterion function suffices

Read more

Summary

Introduction

We develop a general framework for univariate clustering based on the ideas in Hartigan (1978) for the case of observations from a population with smooth and invertible distribution function. One important example is modeling in continuoustime mathematical finance, wherein observations are typically increments from a continuoustime stochastic process, and have smooth distributions because of presence of Ito integral components Keeping this in mind, we deviate from the Hartigan’s framework and concentrate our attention on a function of the derivative of his split function. Holzmann and Vollmer (2008) proposed a parametric test for bimodality based on the likelihood principle by using two-component mixtures Their method was applied to investigate the modal structure of the cross-sectional distribution of per-capita log GDP across EU regions.

Assumptions
Empirical Cross-over Function and Empirical Split Point
Main Results
Numerical Verification
An Example
Discussion

Talk to us

Join us for a 30 min session where you can share your feedback and ask us any queries you have

Schedule a call

Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.