“…For problems to seek α, that is, the one-parameter estimation problems for the lognormal distribution, Wingo (1975Wingo ( , 1976Wingo ( , 1984 has proposed a computing method to avoid the singular range x n − α ≤ δ by adopting a penalty function. On the other hand, for problems to seek simultaneously α, β and γ, where ( α, β, γ) is a PRM, that is, the three-parameter estimation problems (Lambert, 1964) for the distribution, Munro and Wixley (1970) have proposed a parameterization to improve the convergency of many iterative methods (Eastham, LaRiccia and Schuenemeyer, 1987;Hirose, 1997). As seen now, there are two ways for dealing with the parameter estimation of the distribution for complete data.…”