The S-shaped or sigmoidal models have two important members as Logistic model and Gompertz model. These models are very useful in studies of medical science, actuarial science and biological sciences. The proposed linear models are the alternative of Logistic model and Gompertz model respectively. Linear models satisfy the property of best linear unbiased estimator (BLUE) and removed the problem of nonlinear least squares estimation mentioned by Ratkowsky (1983, 1989) and Bates & Watts (1980). The goodness of fit for the proposed linear models have been verified with the help of several published data sets.
Kumar Shukla, Alok; Kumar Yadav, Subhash; and Tiwari, Vishwas
"Linear Models for S-Shaped Growth Curves,"
Journal of Statistics Applications & Probability: Vol. 4
, Article 11.
Available at: https://dc.naturalspublishing.com/jsap/vol4/iss1/11