Least squares fitting of the lognormal curve

Guus A.M. Hart, Hans Oosting, Nico Nagelkerke

Research output: Contribution to journalArticlepeer-review


Problems arising in nonlinear least squares fitting of the first part of the lognormal curve to data are analysed. No evidence of the existence of multiple local minima of the sum of squares has been found. However, it is demonstrated that severe convergence problems might arise, especially if the data points do not indicate the point of inflexion. This is caused by the fact that for small values of the running variable in the lognormal formula with respect to the localisation parameter, the lognormal curve with three parameters can be approximated closely by the exponential curve with two parameters.

Original languageEnglish
Pages (from-to)240-247
Number of pages8
JournalComputers and Biomedical Research
Issue number3
Publication statusPublished - Jun 1981
Externally publishedYes

ASJC Scopus subject areas

  • Medicine (miscellaneous)


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