The three-parameter two-piece normal family of distributions and its fitting

Abstract

This note introduces a family of skew and symmetric distributions containing the normal family and indexed by three parameters with clear meanings. Another respect in which this family compares favourably with families like the Pearson family, the Bessel-Gram-Charlier family and the Johnson family is ease of maximum likelihood fitting. Fitting by the method of moments is also considered. Asymptotic distributions of maximum likelihood and moment estimators are worked out. A test of symmetry and normality is suggested.

Keywords:

• fitting of distribution by maximum likelihood and by rm thod of moments
• asymptotic distribution of estimates
• test of symmetry and normality
• determination of turning points of functions by local fitting of a quadratic